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  • sending a $_SESSION array to my class and attempting to get the value fro it in a for loop .php

    - by eoin
    i have a class which in which iam using a method to get information from a session array via a for loop the 2 for loops in each method are used 1.to count total amount of items , and 2. to add up the total price but neither seem to be returning anything. im using the total amount to check it against the mc_gross posted value from an IPN and if the values are equal i plan to commit the sale to a database as it has been verified. for the method where im looking to get the total price im getting 0.00 returned to me. i think ive got the syntax wrong here somehow here is my class for purchase the two methods iam having trouble with are the gettotalcost() and gettotalitems() shown below is my class. <?php class purchase { private $itemnames; // from session array private $amountofitems; // from session array private $itemcost; //session array private $saleid; //posted transaction id value to be used in sale and sale item tables private $orderdate; //get current date time to be entered as datetime in sale table private $lastname; //posted from ipn private $firstname; //posted from ipn private $emailadd; //uses sessionarray value public function __construct($saleid,$firstname,$lastname) { $this->itemnames = $_SESSION['itemnames']; $this->amountofitems =$_SESSION['quantity']; $this->itemcost =$_SESSION['price']; $this->saleid = $saleid; $this->firstname = $firstname; $this->lastname = $lastname; $this->emailadd = $SESSION['username']; mail($myemail, "session vardump ", echo var_dump($_SESSION), "From: [email protected]" ); mail($myemail, "session vardump ",count($_SESSION['itemnames']) , "From: [email protected]" ); } public function commit() { $databaseinst = database::getinstance(); $databaseinst->connect(); $numrows = $databaseinst->querydb($query); //to be completed } public function gettotalitems() { $numitems; $i; for($i=0; $i < count($this->amountofitems);$i++) { $numitems += (int) $this->amountofitems[$i]; } return $numitems; } public function gettotalcost() { $totalcost; $i; for($i=0; $i < count($this->amountofitems);$i++) { $numitems = (int) $this->amountofitems[$i]; $costofitem =doubleval($this->itemcost [$i]); $totalcost += $numitems * $costofitem; } return $totalcost; } } ?> and here is where i create an instance of the class and attempt to use it. include("purchase.php"); $purchase = new purchase($_POST['txn_id'],$_POST['first_name'],$_POST['last_name']); $fullamount = $purchase->gettotalcost(); $fullAmount = number_format($fullAmount, 2); $grossAmount = $_POST['mc_gross']; if ($fullAmount != $grossAmount) { $message = "Possible Price Jack attempt! the amount the customer payed is : " . $grossAmount . " which is not equal to the full amount. the price of the products combined is " . $fullAmount. " the transaction number for which is " . $_POST['txn_id'] . "\n\n\n$req"; mail("XXXXXXXXXXXX", "Price Jack attempt ", $message, "From: [email protected]" ); exit(); // exit } thanks for the help in advance! ive also added these lines to my constructor. the mail returns that there is nothing in the vardump uh oh! mail($myemailaddress, "session vardump ", var_dump($_SESSION), "From: [email protected]" ); also added session_start(); at the top of the constructor and it dont work! help

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  • 8-Puzzle Solution executes infinitely [migrated]

    - by Ashwin
    I am looking for a solution to 8-puzzle problem using the A* Algorithm. I found this project on the internet. Please see the files - proj1 and EightPuzzle. The proj1 contains the entry point for the program(the main() function) and EightPuzzle describes a particular state of the puzzle. Each state is an object of the 8-puzzle. I feel that there is nothing wrong in the logic. But it loops forever for these two inputs that I have tried : {8,2,7,5,1,6,3,0,4} and {3,1,6,8,4,5,7,2,0}. Both of them are valid input states. What is wrong with the code? Note For better viewing copy the code in a Notepad++ or some other text editor(which has the capability to recognize java source file) because there are lot of comments in the code. Since A* requires a heuristic, they have provided the option of using manhattan distance and a heuristic that calculates the number of misplaced tiles. And to ensure that the best heuristic is executed first, they have implemented a PriorityQueue. The compareTo() function is implemented in the EightPuzzle class. The input to the program can be changed by changing the value of p1d in the main() function of proj1 class. The reason I am telling that there exists solution for the two my above inputs is because the applet here solves them. Please ensure that you select 8-puzzle from teh options in the applet. EDITI gave this input {0,5,7,6,8,1,2,4,3}. It took about 10 seconds and gave a result with 26 moves. But the applet gave a result with 24 moves in 0.0001 seconds with A*. For quick reference I have pasted the the two classes without the comments : EightPuzzle import java.util.*; public class EightPuzzle implements Comparable <Object> { int[] puzzle = new int[9]; int h_n= 0; int hueristic_type = 0; int g_n = 0; int f_n = 0; EightPuzzle parent = null; public EightPuzzle(int[] p, int h_type, int cost) { this.puzzle = p; this.hueristic_type = h_type; this.h_n = (h_type == 1) ? h1(p) : h2(p); this.g_n = cost; this.f_n = h_n + g_n; } public int getF_n() { return f_n; } public void setParent(EightPuzzle input) { this.parent = input; } public EightPuzzle getParent() { return this.parent; } public int inversions() { /* * Definition: For any other configuration besides the goal, * whenever a tile with a greater number on it precedes a * tile with a smaller number, the two tiles are said to be inverted */ int inversion = 0; for(int i = 0; i < this.puzzle.length; i++ ) { for(int j = 0; j < i; j++) { if(this.puzzle[i] != 0 && this.puzzle[j] != 0) { if(this.puzzle[i] < this.puzzle[j]) inversion++; } } } return inversion; } public int h1(int[] list) // h1 = the number of misplaced tiles { int gn = 0; for(int i = 0; i < list.length; i++) { if(list[i] != i && list[i] != 0) gn++; } return gn; } public LinkedList<EightPuzzle> getChildren() { LinkedList<EightPuzzle> children = new LinkedList<EightPuzzle>(); int loc = 0; int temparray[] = new int[this.puzzle.length]; EightPuzzle rightP, upP, downP, leftP; while(this.puzzle[loc] != 0) { loc++; } if(loc % 3 == 0){ temparray = this.puzzle.clone(); temparray[loc] = temparray[loc + 1]; temparray[loc + 1] = 0; rightP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); rightP.setParent(this); children.add(rightP); }else if(loc % 3 == 1){ //add one child swaps with right temparray = this.puzzle.clone(); temparray[loc] = temparray[loc + 1]; temparray[loc + 1] = 0; rightP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); rightP.setParent(this); children.add(rightP); //add one child swaps with left temparray = this.puzzle.clone(); temparray[loc] = temparray[loc - 1]; temparray[loc - 1] = 0; leftP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); leftP.setParent(this); children.add(leftP); }else if(loc % 3 == 2){ // add one child swaps with left temparray = this.puzzle.clone(); temparray[loc] = temparray[loc - 1]; temparray[loc - 1] = 0; leftP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); leftP.setParent(this); children.add(leftP); } if(loc / 3 == 0){ //add one child swaps with lower temparray = this.puzzle.clone(); temparray[loc] = temparray[loc + 3]; temparray[loc + 3] = 0; downP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); downP.setParent(this); children.add(downP); }else if(loc / 3 == 1 ){ //add one child, swap with upper temparray = this.puzzle.clone(); temparray[loc] = temparray[loc - 3]; temparray[loc - 3] = 0; upP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); upP.setParent(this); children.add(upP); //add one child, swap with lower temparray = this.puzzle.clone(); temparray[loc] = temparray[loc + 3]; temparray[loc + 3] = 0; downP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); downP.setParent(this); children.add(downP); }else if (loc / 3 == 2 ){ //add one child, swap with upper temparray = this.puzzle.clone(); temparray[loc] = temparray[loc - 3]; temparray[loc - 3] = 0; upP = new EightPuzzle(temparray, this.hueristic_type, this.g_n + 1); upP.setParent(this); children.add(upP); } return children; } public int h2(int[] list) // h2 = the sum of the distances of the tiles from their goal positions // for each item find its goal position // calculate how many positions it needs to move to get into that position { int gn = 0; int row = 0; int col = 0; for(int i = 0; i < list.length; i++) { if(list[i] != 0) { row = list[i] / 3; col = list[i] % 3; row = Math.abs(row - (i / 3)); col = Math.abs(col - (i % 3)); gn += row; gn += col; } } return gn; } public String toString() { String x = ""; for(int i = 0; i < this.puzzle.length; i++){ x += puzzle[i] + " "; if((i + 1) % 3 == 0) x += "\n"; } return x; } public int compareTo(Object input) { if (this.f_n < ((EightPuzzle) input).getF_n()) return -1; else if (this.f_n > ((EightPuzzle) input).getF_n()) return 1; return 0; } public boolean equals(EightPuzzle test){ if(this.f_n != test.getF_n()) return false; for(int i = 0 ; i < this.puzzle.length; i++) { if(this.puzzle[i] != test.puzzle[i]) return false; } return true; } public boolean mapEquals(EightPuzzle test){ for(int i = 0 ; i < this.puzzle.length; i++) { if(this.puzzle[i] != test.puzzle[i]) return false; } return true; } } proj1 import java.util.*; public class proj1 { /** * @param args */ public static void main(String[] args) { int[] p1d = {1, 4, 2, 3, 0, 5, 6, 7, 8}; int hueristic = 2; EightPuzzle start = new EightPuzzle(p1d, hueristic, 0); int[] win = { 0, 1, 2, 3, 4, 5, 6, 7, 8}; EightPuzzle goal = new EightPuzzle(win, hueristic, 0); astar(start, goal); } public static void astar(EightPuzzle start, EightPuzzle goal) { if(start.inversions() % 2 == 1) { System.out.println("Unsolvable"); return; } // function A*(start,goal) // closedset := the empty set // The set of nodes already evaluated. LinkedList<EightPuzzle> closedset = new LinkedList<EightPuzzle>(); // openset := set containing the initial node // The set of tentative nodes to be evaluated. priority queue PriorityQueue<EightPuzzle> openset = new PriorityQueue<EightPuzzle>(); openset.add(start); while(openset.size() > 0){ // x := the node in openset having the lowest f_score[] value EightPuzzle x = openset.peek(); // if x = goal if(x.mapEquals(goal)) { // return reconstruct_path(came_from, came_from[goal]) Stack<EightPuzzle> toDisplay = reconstruct(x); System.out.println("Printing solution... "); System.out.println(start.toString()); print(toDisplay); return; } // remove x from openset // add x to closedset closedset.add(openset.poll()); LinkedList <EightPuzzle> neighbor = x.getChildren(); // foreach y in neighbor_nodes(x) while(neighbor.size() > 0) { EightPuzzle y = neighbor.removeFirst(); // if y in closedset if(closedset.contains(y)){ // continue continue; } // tentative_g_score := g_score[x] + dist_between(x,y) // // if y not in openset if(!closedset.contains(y)){ // add y to openset openset.add(y); // } // } // } } public static void print(Stack<EightPuzzle> x) { while(!x.isEmpty()) { EightPuzzle temp = x.pop(); System.out.println(temp.toString()); } } public static Stack<EightPuzzle> reconstruct(EightPuzzle winner) { Stack<EightPuzzle> correctOutput = new Stack<EightPuzzle>(); while(winner.getParent() != null) { correctOutput.add(winner); winner = winner.getParent(); } return correctOutput; } }

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  • How-to delete a tree node using the context menu

    - by frank.nimphius
    Hierarchical trees in Oracle ADF make use of View Accessors, which means that only the top level node needs to be exposed as a View Object instance on the ADF Business Components Data Model. This also means that only the top level node has a representation in the PageDef file as a tree binding and iterator binding reference. Detail nodes are accessed through tree rule definitions that use the accessor mentioned above (or nested collections in the case of POJO or EJB business services). The tree component is configured for single node selection, which however can be declaratively changed for users to press the ctrl key and selecting multiple nodes. In the following, I explain how to create a context menu on the tree for users to delete the selected tree nodes. For this, the context menu item will access a managed bean, which then determines the selected node(s), the internal ADF node bindings and the rows they represent. As mentioned, the ADF Business Components Data Model only needs to expose the top level node data sources, which in this example is an instance of the Locations View Object. For the tree to work, you need to have associations defined between entities, which usually is done for you by Oracle JDeveloper if the database tables have foreign keys defined Note: As a general hint of best practices and to simplify your life: Make sure your database schema is well defined and designed before starting your development project. Don't treat the database as something organic that grows and changes with the requirements as you proceed in your project. Business service refactoring in response to database changes is possible, but should be treated as an exception, not the rule. Good database design is a necessity – even for application developers – and nothing evil. To create the tree component, expand the Data Controls panel and drag the View Object collection to the view. From the context menu, select the tree component entry and continue with defining the tree rules that make up the hierarchical structure. As you see, when pressing the green plus icon  in the Edit Tree Binding  dialog, the data structure, Locations -  Departments – Employees in my sample, shows without you having created a View Object instance for each of the nodes in the ADF Business Components Data Model. After you configured the tree structure in the Edit Tree Binding dialog, you press OK and the tree is created. Select the tree in the page editor and open the Structure Window (ctrl+shift+S). In the Structure window, expand the tree node to access the conextMenu facet. Use the right mouse button to insert a Popup  into the facet. Repeat the same steps to insert a Menu and a Menu Item into the Popup you created. The Menu item text should be changed to something meaningful like "Delete". Note that the custom menu item later is added to the context menu together with the default context menu options like expand and expand all. To define the action that is executed when the menu item is clicked on, you select the Action Listener property in the Property Inspector and click the arrow icon followed by the Edit menu option. Create or select a managed bean and define a method name for the action handler. Next, select the tree component and browse to its binding property in the Property Inspector. Again, use the arrow icon | Edit option to create a component binding in the same managed bean that has the action listener defined. The tree handle is used in the action listener code, which is shown below: public void onTreeNodeDelete(ActionEvent actionEvent) {   //access the tree from the JSF component reference created   //using the af:tree "binding" property. The "binding" property   //creates a pair of set/get methods to access the RichTree instance   RichTree tree = this.getTreeHandler();   //get the list of selected row keys   RowKeySet rks = tree.getSelectedRowKeys();   //access the iterator to loop over selected nodes   Iterator rksIterator = rks.iterator();          //The CollectionModel represents the tree model and is   //accessed from the tree "value" property   CollectionModel model = (CollectionModel) tree.getValue();   //The CollectionModel is a wrapper for the ADF tree binding   //class, which is JUCtrlHierBinding   JUCtrlHierBinding treeBinding =                  (JUCtrlHierBinding) model.getWrappedData();          //loop over the selected nodes and delete the rows they   //represent   while(rksIterator.hasNext()){     List nodeKey = (List) rksIterator.next();     //find the ADF node binding using the node key     JUCtrlHierNodeBinding node =                       treeBinding.findNodeByKeyPath(nodeKey);     //delete the row.     Row rw = node.getRow();       rw.remove();   }          //only refresh the tree if tree nodes have been selected   if(rks.size() > 0){     AdfFacesContext adfFacesContext =                          AdfFacesContext.getCurrentInstance();     adfFacesContext.addPartialTarget(tree);   } } Note: To enable multi node selection for a tree, select the tree and change the row selection setting from "single" to "multiple". Note: a fully pictured version of this post will become available at the end of the month in a PDF summary on ADF Code Corner : http://www.oracle.com/technetwork/developer-tools/adf/learnmore/index-101235.html 

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  • RIF PRD: Presentation syntax issues

    - by Charles Young
    Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: ·      Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. ·      Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. ·      Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE          ::= PNAME_LN                  | PNAME_NS PNAME_LN       ::= PNAME_NS PN_LOCAL PNAME_NS       ::= PN_PREFIX? ':' PN_LOCAL       ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS       ::= PN_CHARS_U                  | '-' | [0-9] | #x00B7                  | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U     ::= PN_CHARS_BASE                  | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6]                  | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF]                  | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF]                  | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD]                  | [#x10000-#xEFFFF] PN_PREFIX      ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification.   In any case, RIF does not allow local names without a prefix. ·      Missing ‘External’ specifiers for built-in functions and predicates.  The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. ·      The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. ·      Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant.   All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” ·      The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar.   ·      The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’).   One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. ·      I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. ·      The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars.   I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive.   It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me.  If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document(    Prefix( ex1 <http://example.com/2009/prd2> )    (* ex1:CheckoutRuleset *)  Group rif:forwardChaining (     (* ex1:GoldRule *)    Group 10 (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"Silver"])        (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart]           (If Exists ?value (And(?shoppingCart[ex1:value->?value]                                  External(pred:numeric-greater-than-or-equal(?value 2000))))            Then Do(Modify(?customer[ex1:status->"Gold"])))))      (* ex1:DiscountRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Or( ?customer[ex1:status->"Silver"]                ?customer[ex1:status->"Gold"])         Then Do ((?s ?customer[ex1:shoppingCart-> ?s])                  (?v ?s[ex1:value->?v])                  Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))]))))      (* ex1:NewCustomerAndWidgetRule *)    Group (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"New"] )        (If Exists ?shoppingCart ?item                   (And(?customer[ex1:shoppingCart->?shoppingCart]                        ?shoppingCart[ex1:containsItem->?item]                        ?item # ex1:Widget ) )         Then Do( (?s ?customer[ex1:shoppingCart->?s])                  (?val ?s[ex1:value->?val])                  (?voucher ?customer[ex1:voucher->?voucher])                  Retract(?customer[ex1:voucher->?voucher])                  Retract(?voucher)                  Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))]))))      (* ex1:UnknownStatusRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Not(Exists ?status                       (And(?customer[ex1:status->?status]                            External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) )))         Then Do( Execute(act:print(External(func:concat("New customer: " ?customer))))                  Assert(?customer[ex1:status->"New"]))))  ) )   I hope that helps someone out there :-)

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  • Have suggestions for these assembly mnemonics?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • Retrieving a list of eBay categories using the .NET SDK and GetCategoriesCall

    - by Bill Osuch
    eBay offers a .Net SDK for its Trading API - this post will show you the basics of making an API call and retrieving a list of current categories. You'll need the category ID(s) for any apps that post or search eBay. To start, download the latest SDK from https://www.x.com/developers/ebay/documentation-tools/sdks/dotnet and create a new console app project. Add a reference to the eBay.Service DLL, and a few using statements: using eBay.Service.Call; using eBay.Service.Core.Sdk; using eBay.Service.Core.Soap; I'm assuming at this point you've already joined the eBay Developer Network and gotten your app IDs and user tokens. If not: Join the developer program Generate tokens Next, add an app.config file that looks like this: <?xml version="1.0"?> <configuration>   <appSettings>     <add key="Environment.ApiServerUrl" value="https://api.ebay.com/wsapi"/>     <add key="UserAccount.ApiToken" value="YourBigLongToken"/>   </appSettings> </configuration> And then add the code to get the xml list of categories: ApiContext apiContext = GetApiContext(); GetCategoriesCall apiCall = new GetCategoriesCall(apiContext); apiCall.CategorySiteID = "0"; //Leave this commented out to retrieve all category levels (all the way down): //apiCall.LevelLimit = 4; //Uncomment this to begin at a specific parent category: //StringCollection parentCategories = new StringCollection(); //parentCategories.Add("63"); //apiCall.CategoryParent = parentCategories; apiCall.DetailLevelList.Add(DetailLevelCodeType.ReturnAll); CategoryTypeCollection cats = apiCall.GetCategories(); using (StreamWriter outfile = new StreamWriter(@"C:\Temp\EbayCategories.xml")) {    outfile.Write(apiCall.SoapResponse); } GetApiContext() (provided in the sample apps in the SDK) is required for any call:         static ApiContext GetApiContext()         {             //apiContext is a singleton,             //to avoid duplicate configuration reading             if (apiContext != null)             {                 return apiContext;             }             else             {                 apiContext = new ApiContext();                 //set Api Server Url                 apiContext.SoapApiServerUrl = ConfigurationManager.AppSettings["Environment.ApiServerUrl"];                 //set Api Token to access eBay Api Server                 ApiCredential apiCredential = new ApiCredential();                 apiCredential.eBayToken = ConfigurationManager.AppSettings["UserAccount.ApiToken"];                 apiContext.ApiCredential = apiCredential;                 //set eBay Site target to US                 apiContext.Site = SiteCodeType.US;                 return apiContext;             }         } Running this will give you a large (4 or 5 megs) XML file that looks something like this: <soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">    <soapenv:Body>       <GetCategoriesResponse >          <Timestamp>2012-06-06T16:03:46.158Z</Timestamp>          <Ack>Success</Ack>          <CorrelationID>d02dd9e3-295a-4268-9ea5-554eeb2e0e18</CorrelationID>          <Version>775</Version>          <Build>E775_CORE_BUNDLED_14891042_R1</Build> -          <CategoryArray>             <Category>                <BestOfferEnabled>true</BestOfferEnabled>                <AutoPayEnabled>true</AutoPayEnabled>                <CategoryID>20081</CategoryID>                <CategoryLevel>1</CategoryLevel>                <CategoryName>Antiques</CategoryName>                <CategoryParentID>20081</CategoryParentID>             </Category>             <Category>                <BestOfferEnabled>true</BestOfferEnabled>                <AutoPayEnabled>true</AutoPayEnabled>                <CategoryID>37903</CategoryID>                <CategoryLevel>2</CategoryLevel>                <CategoryName>Antiquities</CategoryName>                <CategoryParentID>20081</CategoryParentID>             </Category> (etc.) You could work with this, but I wanted a nicely nested view, like this: <CategoryArray>    <Category Name='Antiques' ID='20081' Level='1'>       <Category Name='Antiquities' ID='37903' Level='2'/> </CategoryArray> ...so I transformed the xml: private void TransformXML(CategoryTypeCollection cats)         {             XmlElement topLevelElement = null;             XmlElement childLevelElement = null;             XmlNode parentNode = null;             string categoryString = "";             XmlDocument returnDoc = new XmlDocument();             XmlElement root = returnDoc.CreateElement("CategoryArray");             returnDoc.AppendChild(root);             XmlNode rootNode = returnDoc.SelectSingleNode("/CategoryArray");             //Loop through CategoryTypeCollection             foreach (CategoryType category in cats)             {                 if (category.CategoryLevel == 1)                 {                     //Top-level category, so we know we can just add it                     topLevelElement = returnDoc.CreateElement("Category");                     topLevelElement.SetAttribute("Name", category.CategoryName);                     topLevelElement.SetAttribute("ID", category.CategoryID);                     rootNode.AppendChild(topLevelElement);                 }                 else                 {                     // Level number will determine how many Category nodes we are deep                     categoryString = "";                     for (int x = 1; x < category.CategoryLevel; x++)                     {                         categoryString += "/Category";                     }                     parentNode = returnDoc.SelectSingleNode("/CategoryArray" + categoryString + "[@ID='" + category.CategoryParentID[0] + "']");                     childLevelElement = returnDoc.CreateElement("Category");                     childLevelElement.SetAttribute("Name", category.CategoryName);                     childLevelElement.SetAttribute("ID", category.CategoryID);                     parentNode.AppendChild(childLevelElement);                 }             }             returnDoc.Save(@"C:\Temp\EbayCategories-Modified.xml");         } Yes, there are probably much cleaner ways of dealing with it, but I'm not an xml expert… Keep in mind, eBay categories do not change on a regular basis, so you should be able to cache this data (either in a file or database) for some time. The xml returns a CategoryVersion node that you can use to determine if the category list has changed. Technorati Tags: Csharp, eBay

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  • Are their any suggestions for this new assembly language?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller exit End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • RiverTrail - JavaScript GPPGU Data Parallelism

    - by JoshReuben
    Where is WebCL ? The Khronos WebCL working group is working on a JavaScript binding to the OpenCL standard so that HTML 5 compliant browsers can host GPGPU web apps – e.g. for image processing or physics for WebGL games - http://www.khronos.org/webcl/ . While Nokia & Samsung have some protype WebCL APIs, Intel has one-upped them with a higher level of abstraction: RiverTrail. Intro to RiverTrail Intel Labs JavaScript RiverTrail provides GPU accelerated SIMD data-parallelism in web applications via a familiar JavaScript programming paradigm. It extends JavaScript with simple deterministic data-parallel constructs that are translated at runtime into a low-level hardware abstraction layer. With its high-level JS API, programmers do not have to learn a new language or explicitly manage threads, orchestrate shared data synchronization or scheduling. It has been proposed as a draft specification to ECMA a (known as ECMA strawman). RiverTrail runs in all popular browsers (except I.E. of course). To get started, download a prebuilt version https://github.com/downloads/RiverTrail/RiverTrail/rivertrail-0.17.xpi , install Intel's OpenCL SDK http://www.intel.com/go/opencl and try out the interactive River Trail shell http://rivertrail.github.com/interactive For a video overview, see  http://www.youtube.com/watch?v=jueg6zB5XaM . ParallelArray the ParallelArray type is the central component of this API & is a JS object that contains ordered collections of scalars – i.e. multidimensional uniform arrays. A shape property describes the dimensionality and size– e.g. a 2D RGBA image will have shape [height, width, 4]. ParallelArrays are immutable & fluent – they are manipulated by invoking methods on them which produce new ParallelArray objects. ParallelArray supports several constructors over arrays, functions & even the canvas. // Create an empty Parallel Array var pa = new ParallelArray(); // pa0 = <>   // Create a ParallelArray out of a nested JS array. // Note that the inner arrays are also ParallelArrays var pa = new ParallelArray([ [0,1], [2,3], [4,5] ]); // pa1 = <<0,1>, <2,3>, <4.5>>   // Create a two-dimensional ParallelArray with shape [3, 2] using the comprehension constructor var pa = new ParallelArray([3, 2], function(iv){return iv[0] * iv[1];}); // pa7 = <<0,0>, <0,1>, <0,2>>   // Create a ParallelArray from canvas.  This creates a PA with shape [w, h, 4], var pa = new ParallelArray(canvas); // pa8 = CanvasPixelArray   ParallelArray exposes fluent API functions that take an elemental JS function for data manipulation: map, combine, scan, filter, and scatter that return a new ParallelArray. Other functions are scalar - reduce  returns a scalar value & get returns the value located at a given index. The onus is on the developer to ensure that the elemental function does not defeat data parallelization optimization (avoid global var manipulation, recursion). For reduce & scan, order is not guaranteed - the onus is on the dev to provide an elemental function that is commutative and associative so that scan will be deterministic – E.g. Sum is associative, but Avg is not. map Applies a provided elemental function to each element of the source array and stores the result in the corresponding position in the result array. The map method is shape preserving & index free - can not inspect neighboring values. // Adding one to each element. var source = new ParallelArray([1,2,3,4,5]); var plusOne = source.map(function inc(v) {     return v+1; }); //<2,3,4,5,6> combine Combine is similar to map, except an index is provided. This allows elemental functions to access elements from the source array relative to the one at the current index position. While the map method operates on the outermost dimension only, combine, can choose how deep to traverse - it provides a depth argument to specify the number of dimensions it iterates over. The elemental function of combine accesses the source array & the current index within it - element is computed by calling the get method of the source ParallelArray object with index i as argument. It requires more code but is more expressive. var source = new ParallelArray([1,2,3,4,5]); var plusOne = source.combine(function inc(i) { return this.get(i)+1; }); reduce reduces the elements from an array to a single scalar result – e.g. Sum. // Calculate the sum of the elements var source = new ParallelArray([1,2,3,4,5]); var sum = source.reduce(function plus(a,b) { return a+b; }); scan Like reduce, but stores the intermediate results – return a ParallelArray whose ith elements is the results of using the elemental function to reduce the elements between 0 and I in the original ParallelArray. // do a partial sum var source = new ParallelArray([1,2,3,4,5]); var psum = source.scan(function plus(a,b) { return a+b; }); //<1, 3, 6, 10, 15> scatter a reordering function - specify for a certain source index where it should be stored in the result array. An optional conflict function can prevent an exception if two source values are assigned the same position of the result: var source = new ParallelArray([1,2,3,4,5]); var reorder = source.scatter([4,0,3,1,2]); // <2, 4, 5, 3, 1> // if there is a conflict use the max. use 33 as a default value. var reorder = source.scatter([4,0,3,4,2], 33, function max(a, b) {return a>b?a:b; }); //<2, 33, 5, 3, 4> filter // filter out values that are not even var source = new ParallelArray([1,2,3,4,5]); var even = source.filter(function even(iv) { return (this.get(iv) % 2) == 0; }); // <2,4> Flatten used to collapse the outer dimensions of an array into a single dimension. pa = new ParallelArray([ [1,2], [3,4] ]); // <<1,2>,<3,4>> pa.flatten(); // <1,2,3,4> Partition used to restore the original shape of the array. var pa = new ParallelArray([1,2,3,4]); // <1,2,3,4> pa.partition(2); // <<1,2>,<3,4>> Get return value found at the indices or undefined if no such value exists. var pa = new ParallelArray([0,1,2,3,4], [10,11,12,13,14], [20,21,22,23,24]) pa.get([1,1]); // 11 pa.get([1]); // <10,11,12,13,14>

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  • Are there any suggestions for these new assembly mnemonics?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • Mscorlib mocking minus the attribute

    - by mehfuzh
    Mocking .net framework members (a.k.a. mscorlib) is always a daunting task. It’s the breed of static and final methods and full of surprises. Technically intercepting mscorlib members is completely different from other class libraries. This is the reason it is dealt differently. Generally, I prefer writing a wrapper around an mscorlib member (Ex. File.Delete(“abc.txt”)) and expose it via interface but that is not always an easy task if you already have years old codebase. While mocking mscorlib members first thing that comes to people’s mind is DateTime.Now. If you Google through, you will find tons of example dealing with just that. May be it’s the most important class that we can’t ignore and I will create an example using JustMock Q2 with the same. In Q2 2012, we just get rid of the MockClassAtrribute for mocking mscorlib members. JustMock is already attribute free for mocking class libraries. We radically think that vendor specific attributes only makes your code smelly and therefore decided the same for mscorlib. Now, I want to fake DateTime.Now for the following class: public class NestedDateTime { public DateTime GetDateTime() { return DateTime.Now; } } It is the simplest one that can be. The first thing here is that I tell JustMock “hey we have a DateTime.Now in NestedDateTime class that we want to mock”. To do so, during the test initialization I write this: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Mock.Replace(() => DateTime.Now).In<NestedDateTime>(x => x.GetDateTime());.csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I can also define it for all the members in the class, but that’s just a waste of extra watts. Mock.Replace(() => DateTime.Now).In<NestedDateTime>(); Now question, why should I bother doing it? The answer is that I am not using attribute and with this approach, I can mock any framework members not just File, FileInfo or DateTime. Here to note that we already mock beyond the three but when nested around a complex class, JustMock was not intercepting it correctly. Therefore, we decided to get rid of the attribute altogether fixing the issue. Finally, I write my test as usual. [TestMethod] public void ShouldAssertMockingDateTimeFromNestedClass() { var expected = new DateTime(2000, 1, 1); Mock.Arrange(() => DateTime.Now).Returns(expected); Assert.Equal(new NestedDateTime().GetDateTime(), expected); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } That’s it, we are good. Now let me do the same for a random one, let’s say I want mock a member from DriveInfo: Mock.Replace<DriveInfo[]>(() => DriveInfo.GetDrives()).In<MsCorlibFixture>(x => x.ShouldReturnExpectedDriveWhenMocked()); Moving forward, I write my test: [TestMethod] public void ShouldReturnExpectedDriveWhenMocked() { Mock.Arrange(() => DriveInfo.GetDrives()).MustBeCalled(); DriveInfo.GetDrives(); Mock.Assert(()=> DriveInfo.GetDrives()); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here is one convention; you have to replace the mscorlib member before executing the target method that contains it. Here the call to DriveInfo is within the MsCorlibFixture therefore it should be defined during test initialization or before executing the test method. Hope this gives you the idea.

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  • Possible SWITCH Optimization in DAX – #powerpivot #dax #tabular

    - by Marco Russo (SQLBI)
    In one of the Advanced DAX Workshop I taught this year, I had an interesting discussion about how to optimize a SWITCH statement (which could be frequently used checking a slicer, like in the Parameter Table pattern). Let’s start with the problem. What happen when you have such a statement? Sales :=     SWITCH (         VALUES ( Period[Period] ),         "Current", [Internet Total Sales],         "MTD", [MTD Sales],         "QTD", [QTD Sales],         "YTD", [YTD Sales],          BLANK ()     ) The SWITCH statement is in reality just syntax sugar for a nested IF statement. When you place such a measure in a pivot table, for every cell of the pivot table the IF options are evaluated. In order to optimize performance, the DAX engine usually does not compute cell-by-cell, but tries to compute the values in bulk-mode. However, if a measure contains an IF statement, every cell might have a different execution path, so the current implementation might evaluate all the possible IF branches in bulk-mode, so that for every cell the result from one of the branches will be already available in a pre-calculated dataset. The price for that could be high. If you consider the previous Sales measure, the YTD Sales measure could be evaluated for all the cells where it’s not required, and also when YTD is not selected at all in a Pivot Table. The actual optimization made by the DAX engine could be different in every build, and I expect newer builds of Tabular and Power Pivot to be better than older ones. However, we still don’t live in an ideal world, so it could be better trying to help the engine finding a better execution plan. One student (Niek de Wit) proposed this approach: Selection := IF (     HASONEVALUE ( Period[Period] ),     VALUES ( Period[Period] ) ) Sales := CALCULATE (     [Internet Total Sales],     FILTER (         VALUES ( 'Internet Sales'[Order Quantity] ),         'Internet Sales'[Order Quantity]             = IF (                 [Selection] = "Current",                 'Internet Sales'[Order Quantity],                 -1             )     ) )     + CALCULATE (         [MTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "MTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     )     + CALCULATE (         [QTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "QTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     )     + CALCULATE (         [YTD Sales],         FILTER (             VALUES ( 'Internet Sales'[Order Quantity] ),             'Internet Sales'[Order Quantity]                 = IF (                     [Selection] = "YTD",                     'Internet Sales'[Order Quantity],                     -1                 )         )     ) At first sight, you might think it’s impossible that this approach could be faster. However, if you examine with the profiler what happens, there is a different story. Every original IF’s execution branch is now a separate CALCULATE statement, which applies a filter that does not execute the required measure calculation if the result of the FILTER is empty. I used the ‘Internet Sales’[Order Quantity] column in this example just because in Adventure Works it has only one value (every row has 1): in the real world, you should use a column that has a very low number of distinct values, or use a column that has always the same value for every row (so it will be compressed very well!). Because the value –1 is never used in this column, the IF comparison in the filter discharge all the values iterated in the filter if the selection does not match with the desired value. I hope to have time in the future to write a longer article about this optimization technique, but in the meantime I’ve seen this optimization has been useful in many other implementations. Please write your feedback if you find scenarios (in both Power Pivot and Tabular) where you obtain performance improvements using this technique!

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  • We've completed the first iteration

    - by CliveT
    There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

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  • Redirecting to a dynamic page

    - by binarydev
    I have a page displaying blog posts (latest_posts.php) and another page that display single blog posts (blog.php) . I intend to link the image title in latest_posts.php so that it redirects to blog.php where it would display the particular post that was clicked. latest_posts.php: <!-- Header --> <h2 class="underline"> <span>What&#039;s new</span> <span></span> </h2> <!-- /Header --> <!-- Posts list --> <ul class="post-list post-list-1"> <?php /* Fetches Date/Time, Post Content and title */ include 'dbconnect.php'; $sql = "SELECT * FROM wp_posts"; $res = mysql_query($sql); while ( $row = mysql_fetch_array($res) ) { ?> <!-- Post #1 --> <li class="clear-fix"> <!-- Date --> <div class="post-list-date"> <div class="post-date-box"> <?php //Timestamp broken down to show accordingly $timestamp = $row['post_date']; $datetime = new DateTime($timestamp); $date = $datetime->format("d"); $month = $datetime->format("M"); ?> <h3> <?php echo $date; ?> </h3> <span> <?php echo $month; ?> </span> </div> </div> <!-- /Date --> <!-- Image + comments count --> <div class="post-list-image"> <!-- Image --> <div class="image image-overlay-url image-fancybox-url"> <a href="post.php" class="preloader-image"> <?php echo '<img src="', $row['image'], '" alt="' , $row['post_title'] , '\'s Blog Image" />'; ?> </a> </div> <!-- /Image --> </div> <!-- /Image + comments count --> <!-- Content --> <div class="post-list-content"> <div> <!-- Header --> <h4> <a href="post.php? . $row['ID'] . "> <?php echo $row['post_title']; ?> </a> </h4> <!-- /Header --> <!-- Excerpt --> <p> <?php echo $row ['post_content']; }?> </p> <!-- /Excerpt --> </div> </div> <!-- /Content --> </li> <!-- /Post #1 --> </ul> <!-- /Posts list --> <a href="blog.php" class="button-browse">Browse All Posts</a> </div> <?php require_once('include/twitter_user_timeline.php'); ?> blog.php: <?php require_once('include/header.php'); ?> <body class="blog"> <?php require_once('include/navigation_bar_blog.php'); ?> <div class="blog"> <div class="main"> <!-- Header --> <h2 class="underline"> <span>What&#039;s new</span> <span></span> </h2> <!-- /Header --> <!-- Layout 66x33 --> <div class="layout-p-66x33 clear-fix"> <!-- Left column --> <!-- <div class="column-left"> --> <!-- Posts list --> <ul class="post-list post-list-2"> <?php /* Fetches Date/Time, Post Content and title with Pagination */ include 'dbconnect.php'; //sets to default page if(empty($_GET['pn'])){ $page=1; } else { $page = $_GET['pn']; } // Index of the page $index = ($page-1)*3; $sql = "SELECT * FROM `wp_posts` ORDER BY `post_date` DESC LIMIT " . $index . " ,3"; $res = mysql_query($sql); //Loops through the values while ( $row = mysql_fetch_array($res) ) { ?> <!-- Post #1 --> <li class="clear-fix"> <!-- Date --> <div class="post-list-date"> <div class="post-date-box"> <?php //Timestamp broken down to show accordingly $timestamp = $row['post_date']; $datetime = new DateTime($timestamp); $date = $datetime->format("d"); $month = $datetime->format("M"); ?> <h3> <?php echo $date; ?> </h3> <span> <?php echo $month; ?> </span> </div> </div> <!-- /Date --> <!-- Image + comments count --> <div class="post-list-image"> <!-- Image --> <div class="image image-overlay-url image-fancybox-url"> <a href="post.php" class="preloader-image"> <?php echo '<img src="', $row['image'], '" alt="' , $row['post_title'] , '\'s Blog Image" />'; ?> </a> </div> <!-- /Image --> </div> <!-- /Image + comments count --> <!-- Content --> <div class="post-list-content"> <div> <?php $id = $_GET['ID']; $post = lookup_post_somehow($id); if($post) { // render post } else { echo 'blog post not found..'; } ?> <!-- Header --> <h4> <a href="post.php"> <?php echo $row['post_title']; ?> </a> </h4> <!-- /Header --> <!-- Excerpt --> <p> <?php echo $row ['post_content']; ?> </p> <!-- /Excerpt --> </div> </div> <!-- /Content --> </li> <!-- /Post #1 --> <?php } // close while loop ?> </ul> <!-- /Posts list --> <div><!-- Pagination --> <ul class="blog-pagination clear-fix"> <?php //Count the number of rows $numberofrows = mysql_query("SELECT COUNT(ID) FROM `wp_posts`"); //Do ciel() to round the result according to number of posts $postsperpage = 4; $numOfPages = ceil($numberofrows / $postsperpage); for($i=1; $i < $numOfPages; $i++) { //echos links for each page $paginationDisplay = '<li><a href="blog.php?pn=' . $i . '">' . $i . '</a></li>'; echo $paginationDisplay; } ?> <!-- <li><a href="#" class="selected">1</a></li> <li><a href="#">2</a></li> <li><a href="#">3</a></li> <li><a href="#">4</a></li> --> </ul> </div><!-- /Pagination --> <!-- /div> --> <!-- Left column --> </div> <!-- /Layout 66x33 --> </div> </div> <?php require_once('include/twitter_user_timeline.php'); ?> <?php require_once('include/footer_blog.php'); ?> How do I render?

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  • Where do I start ?

    - by Panthe
    Brief History: Just graduated high school, learned a bit of python and C++, have no friends with any helpful computer knowledge at all. Out of anyone i met in my school years I was probably the biggest nerd, but no one really knew. I consider my self to have a vast amount of knowledge on computers and tech then the average person. built/fixed tons of computers, and ability to troubleshoot pretty much any problem I came across. Now that high school is over, Ive really been thinking about my career. Loving, living computers for the past 15 years of my life I decided to take my ability's and try to learn computer programming, why I didn't start earlier I don't know, seems to be big mistake on my part... Doing some research I concluded that Python was the first programming language I should learn, since it was high level and easier to understand then C++ and Java. I also knew that to become good at what I did I needed to know more then just 2 or 3 languages, which didn't seem like a big problem considering once I learned the way Python worked, mainly syntax changed, and the rest would come naturally. I watched a couple of youtube videos, downloaded some book pdf's and snooped around from some tutorials here and there to get the hang of what to do. A two solid weeks had passed of trying to understand the syntax, create small programs that used the basic functions and understanding how it worked, I think i have got the hang of it. It breaks down into what ive been dealing with all this time (although i kinda knew) is that, input,output, loops, functions and other things derived from 0's and 1's storing data and recalling it, ect. (A VERY BASIC IDEA). Ive been able to create small programs, Hangman, file storing, temperature conversion, Caeser Cipher decode/encoding, Fibonacci Sequence and more, which i can create and understand how each work. Being 2 weeks into this, I have learned alot. Nothing at all compared to what i should be learning in the years to come if i get a grip on what I'm doing. While doing these programs I wont stop untill I've done doing a practice problem on a book, which embarresing enough will take me a couple hour depending on the complexity of it. I absolutly will not put aside the challenge until its complete, WHICH CAN BE EXTREMELY DRAINING, ive tried most problems without cheating and reached success, which makes me feel extremely proud of my self after completing something after much trial and error. After all this I have met the demon, alogrithm's which seem to be key to effiecent code. I cant seem to rap my head around some of the computer codes people put out there using numbers, and sometimes even basic functions, I have been able to understand them after a while but i know there are alot more complex things to come, considering my self smart, functions that require complex codes, actually hurt my brain. NOTHING EVER IN LIFE HURT MY BRAIN....... not even math classes in highschool, trying to understand some of the stuff people put out there makes me feel like i have a mental disadvantage lol... i still walk forward though, crossing my fingers that the understanding will come with time. Sorry if is this is long i just wish someone takes all these things into consideration when answering my question. even through all these downsides im still pushing through and continuing to try and get good at this, i know reading these tutorials wont make me any good unless i can become creative and make my own, understand other peoples programs, so this leads me to the simple question i could have asked in the beginning..... WHERE IN THE WORLD DO I START ? Ive been trying to find out how to understand some of the open source projects, how i can work with experianced coders to learn from them and help them, but i dont think thats even possible by the way how far people's knowledge is compared to me, i have no freinds who i can learn from, can someone help me and guide me into the right direction.. i have a huge motivation to get good at coding, anything information would be extremely helpful

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  • How do I use constructor dependency injection to supply Models from a collection to their ViewModels

    - by GraemeF
    I'm using constructor dependency injection in my WPF application and I keep running into the following pattern, so would like to get other people's opinion on it and hear about alternative solutions. The goal is to wire up a hierarchy of ViewModels to a similar hierarchy of Models, so that the responsibility for presenting the information in each model lies with its own ViewModel implementation. (The pattern also crops up under other circumstances but MVVM should make for a good example.) Here's a simplified example. Given that I have a model that has a collection of further models: public interface IPerson { IEnumerable<IAddress> Addresses { get; } } public interface IAddress { } I would like to mirror this hierarchy in the ViewModels so that I can bind a ListBox (or whatever) to a collection in the Person ViewModel: public interface IPersonViewModel { ObservableCollection<IAddressViewModel> Addresses { get; } void Initialize(); } public interface IAddressViewModel { } The child ViewModel needs to present the information from the child Model, so it's injected via the constructor: public class AddressViewModel : IAddressViewModel { private readonly IAddress _address; public AddressViewModel(IAddress address) { _address = address; } } The question is, what is the best way to supply the child Model to the corresponding child ViewModel? The example is trivial, but in a typical real case the ViewModels have more dependencies - each of which has its own dependencies (and so on). I'm using Unity 1.2 (although I think the question is relevant across the other IoC containers), and I am using Caliburn's view strategies to automatically find and wire up the appropriate View to a ViewModel. Here is my current solution: The parent ViewModel needs to create a child ViewModel for each child Model, so it has a factory method added to its constructor which it uses during initialization: public class PersonViewModel : IPersonViewModel { private readonly Func<IAddress, IAddressViewModel> _addressViewModelFactory; private readonly IPerson _person; public PersonViewModel(IPerson person, Func<IAddress, IAddressViewModel> addressViewModelFactory) { _addressViewModelFactory = addressViewModelFactory; _person = person; Addresses = new ObservableCollection<IAddressViewModel>(); } public ObservableCollection<IAddressViewModel> Addresses { get; private set; } public void Initialize() { foreach (IAddress address in _person.Addresses) Addresses.Add(_addressViewModelFactory(address)); } } A factory method that satisfies the Func<IAddress, IAddressViewModel> interface is registered with the main UnityContainer. The factory method uses a child container to register the IAddress dependency that is required by the ViewModel and then resolves the child ViewModel: public class Factory { private readonly IUnityContainer _container; public Factory(IUnityContainer container) { _container = container; } public void RegisterStuff() { _container.RegisterInstance<Func<IAddress, IAddressViewModel>>(CreateAddressViewModel); } private IAddressViewModel CreateAddressViewModel(IAddress model) { IUnityContainer childContainer = _container.CreateChildContainer(); childContainer.RegisterInstance(model); return childContainer.Resolve<IAddressViewModel>(); } } Now, when the PersonViewModel is initialized, it loops through each Address in the Model and calls CreateAddressViewModel() (which was injected via the Func<IAddress, IAddressViewModel> argument). CreateAddressViewModel() creates a temporary child container and registers the IAddress model so that when it resolves the IAddressViewModel from the child container the AddressViewModel gets the correct instance injected via its constructor. This seems to be a good solution to me as the dependencies of the ViewModels are very clear and they are easily testable and unaware of the IoC container. On the other hand, performance is OK but not great as a lot of temporary child containers can be created. Also I end up with a lot of very similar factory methods. Is this the best way to inject the child Models into the child ViewModels with Unity? Is there a better (or faster) way to do it in other IoC containers, e.g. Autofac? How would this problem be tackled with MEF, given that it is not a traditional IoC container but is still used to compose objects?

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  • WPF BackgroundWorker Execution

    - by Sanju
    Hi All, I've been programming C# for a while now (I'm a Computer Science major), and have never had to implement threading. I am currently building an application for a client that requires threading for a series of operations. Due to the nature of the client/provider agreement, I cannot release the source I am working with. The code that I have posted is in a general form. Pretty much the basic idea of what I am implementing, excluding the content specific source. The first Snippet demonstrates my basic structure, The Progress class is a custom progress window that is displayed as a dialog to prevent user UI interaction. I am currently using the code to complete database calls based on a collection of objects in another area of the application code. For example, I have a collection of "Objects" of one of my custom classes, that I perform these database calls on or on behalf of. My current set up works just fine when I call the "GeneralizedFunction" one and only one time. What I need to do is call this function once for every object in the collection. I was attempting to use a foreach loop to iterate through the collection, then I tried a for loop. For both loops, the result was the same. The Async operation performs exactly as desired for the first item in the collection. This, however, is the only one it works for. For each subsequent item, the progress box (my custom window) displays and immediately closes. In terms of the database calls, the calls for the first item in the collection are the only ones that successfully complete. All others aren't attempted. I've tried everything that I know and don't know to do, but I just cannot seem to get it to work. How can I get this to work for my entire collection? Any and all help is very greatly appreciated. Progress progress; BackgroundWorker worker; // Cancel the current process private void CancelProcess(object sender, EventArgs e) { worker.CancelAsync(); } // The main process ... "Generalized" private void GeneralizedFunction() { progress = new Progress(); progress.Cancel += CancelProcess; progress.Owner = this; Dispatcher pDispatcher = progress.Dispatcher; worker = new BackgroundWorker(); worker.WorkerSupportsCancellation = true; object[] workArgs = { arg1, arg2, arg3}; worker.DoWork += delegate(object s, DoWorkEventArgs args) { /* All main logic here */ foreach(Class ClassObject in ClassObjectCollection) { //Some more logic here UpdateProgressDelegate update = new UpdateProgressDelegate(updateProgress); pDispatcher.BeginInvoke(update, arg1,arg2,arg3); Thread.Sleep(1000); } }; worker.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs args) { progress.Close(); }; worker.RunWorkerAsync(workArgs); progress.ShowDialog(); } public delegate void UpdateProgressDelegate(arg1,arg2,arg3); private void updateProgress(arg1,arg2,arg3) { //Update progress }

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  • Recursing data into a 2 dimensional array in PHP 5

    - by user315699
    I'm getting bamboozled by "for each" loops and two dimensional arrays, and I'm a php newb so please bear with me (and ignore any variables with the word "image" - it's all about the mp3s, I just didn't change it from the xml tutorial) I found a php function on the net that list files in a directory, the output of which is: Array ( [0] = audio/1.mp3 [1] = audio/2.mp3 [2] = audio/3.mp3 [3] = audio/4.mp3 [4] = audio/5.mp3 ) As expected. And another that lists some info about mp3 files. $mp3datafile = 'audio/1.mp3'; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); print_r($mp3dataArray); unset($mp3dataArray); The output of which is Array ( [Filesize] = 31972 [Encoding] = CBR [etc] ) In order to automatically build RSS for a podcast, I need to generate XML for each item. So far so good. This is how I'm making the xml foreach ($imagearray as $key = $val) { $tnsoundfile = $xml_generator-addChild('item'); $tnsoundfile-addChild('title', $podcasttitle); $enclosure = $tnsoundfile-addChild('enclosure'); $enclosure-addAttribute('url', $val); // that's the filename $enclosure-addAttribute('length', $mp3dataArray[Filesize]); // << Length is file length, not time. But later I also need $mp3dataArray[Length mm:ss] for duration tag. $enclosure-addAttribute('type', 'audio/mpeg'); $tnsoundfile-addChild('guid', $path_to_image_dir.'/'.$val); } (The above has been truncated, I realise it's not proper xml right now, but it was just to show what was going on). Perfect. But I need to do it for as many files as there are in the directory. So, I have an array of the names of the files in the directory in $mp3data And, I have an array of mp3 data in $mp3dataArray from one iteration of the get_metadata() function. If I do the following, then I get a nice list of the mp3 data of the 5 files in the directory: foreach ($mp3data as $key = $val) { $mp3datafile = $val; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); print_r($mp3dataArray); unset($mp3dataArray); } As expected. Where I'm struggling, and have been for most of the day in spite of reading many forums and tutorials, is how to populate the "second dimension" of the array, so that it goes through 1,2,3,4 and 5.mp3 (or however many there are), extracts the metadata, then allows me to use it in the xml section above. Here's what I have foreach ($mp3data as $key = $val) { $mp3datafile = $val; $m = new mp3file($mp3datafile); $mp3dataArray = $m-get_metadata(); $mp3testarray = array($mp3dataArray); } print_r($mp3dataArray); Shouldn't that line print_r($mp3dataArray); give me a nice list of 5 lots of mp3 data, in the way it did when I recursed through the loop as before? Cos this is driving me nuts! It must be something so simple, and any help would be greatly appreciated. Thank you in advance.

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  • C socket: problem with connect() and/or accept() between clients. 111: Connection refused

    - by Fantastic Fourier
    Hello ladies and gents, I'm having a bit of problem with accept(). I have a multiple clients and one server. The clients can connect and communicate just fine with server. But at one point, I need some clients to be directly connected to each other and I'm having a bit of difficulty there. The clients have bunch of threads going on, where one of them is handle_connection() and it has a while(1), looping forever to listen() and accept() whatever incoming connections. Whenever a client tries to connect() to other client, connect() returns an error, 111: Connection Refused. I know I have the right IP address and right port (I have specified a port just for between-client connections). The client that is waiting for connection doesn't notice anything, no new connection, nada. I copied some parts of the code, in hopes that someone can point out what I'm doing wrong. Thanks for any inputs! This is all client side code. void * handle_connections(void * arg) is a thread that loops forever to accept() any incoming connections. My server has a very similar thang going on and it works very well. (not sure why it doesn't work here..) This is the part of client that is waiting for a new incoming connection. int handle_request(void * arg, struct message * msg) is called at one point during program and tries to connect to a client that is specified in struct message * msg which includes struct sockaddr_in with IP address and port number and whatever. #define SERVER_PORT 10000 #define CLIENT_PORT 3456 #define MAX_CONNECTION 20 #define MAX_MSG 50 void * handle_connections(void * arg) { struct fd_info * info; struct sockaddr_in client_address; struct timeval timeout; fd_set readset, copyset; bzero((char * ) &client_address, sizeof(client_address)); // copy zeroes into string client_address.sin_family = AF_INET; client_address.sin_addr.s_addr = htonl(INADDR_ANY); client_address.sin_port = htons(CLIENT_PORT); sockfd = socket(AF_INET, SOCK_STREAM, 0); rv = listen(sockfd,MAX_CONNECTION); while(1) { new_sockfd = accept(sockfd, (struct sockaddr *) &client_address, &client_addr_len); //blocks if (new_sockfd < 0) { printf("C: ERROR accept() %i: %s \n", errno, strerror(errno)); sleep(2); } else { printf("C: accepted\n"); FD_SET(new_sockfd, &readset); // sets bit for new_sockfd to list of sockets to watch out for if (maxfd < new_sockfd) maxfd = new_sockfd; if (minfd > new_sockfd) minfd = new_sockfd; } //end if else (new_sockfd) } // end of the forever while loop } int handle_request(void * arg, struct message * msg) { char * cname, gname, payload; char * command[3]; int i, rv, sockfd, client_addr_len; struct sockaddr_in client_address; struct fd_info * info; info = (struct fd_info *) arg; sockfd = info->sock_fd; sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd == -1) { printf("HR: ERROR socket() %i: %s \n", errno, strerror(errno)); break; } else if (sockfd > 0) { printf("HR: new socks is %i \n", sockfd); printf("HR: sin_family is %i: %i\n", msg->peer.client_address.sin_family, msg->peer.client_address.sin_port); //************************************************************* //this is the part that returns error 111: Connection refused!!! //************************************************************* rv = connect(sockfd, (struct sockaddr *) &msg->peer.client_address, sizeof(struct sockaddr)); if (rv == -1) { printf("HR: ERROR: connect() %i: %s \n", errno, strerror(errno)); printf("HR: at %li \n", msg->peer.client_address.sin_addr.s_addr); break; } else if (rv > 0) { info->max_fd = sockfd; printf("HR: connected successfully!! \n"); } } }

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  • Calculated Fields - Idiosyncracies

    - by PointsToShare
    © 2011 By: Dov Trietsch. All rights reserved Calculated Fields and some of their Idiosyncrasies Did you try to write a calculate field formula directly into the screen? Good Luck – You’ll need it! Calculated Fields are a sophisticated OOB feature of SharePoint, so you could think that they are best left to the end users – at least to the power users. But they reach their limits before the “Professionals “do, and the tough ones come back to us anyway. Back to business; the simpler the formula, the easier it is. Still, use your favorite editor to write it, then cut it and paste it to the ridiculously small window. What about complex formulae? Write them in steps! Here is a case in point and an idiosyncrasy or two. Our welders need to be certified and recertified every two years. Some of them are certifiable…., but I digress. To be certified you need to pass an eye exam, and two more tests – test A and test B. for each of those you have an expiry date. When renewed, each expiry date is advanced by two years from the date of renewal. My users wanted a visual clue so that when the supervisor looks at the list, she’ll have a KPI symbol telling her if anything expired (Red), is going to expire within the next 90 days (Yellow) or is not to be worried about (green). Not all the dates are filled and any blank date implies a complete lack of certification in the particular requirement. Obviously, I needed to figure the minimal of these 3 dates – a simple enough formula: =MIN([Date_EyeExam], {Date_TestA], [Date_TestB]). Aha! Here is idiosyncrasy #1. When one of the dates is a null, MIN(Date1, Date2) returns the non null date. Null is construed as “Far, far away”. The funny thing is that when you compare it to Today, the null is the lesser one. So a null it is less than today, but not when MIN is calculated. Now, to me the fact that the welder does not have an exam date, is synonymous with his exam being prehistoric, or at least past due. So here is what I did: Solution: Let’s set a blank date to 1/1/1800. How will we do that? Use the IF. IF([Field] rel relValue, TrueValue, FalseValue). rel is any relationship operator <, >, <=, >=, =, <>. If the field is related to the relValue as prescribed, the “IF” returns the TrueValue, otherwise it returns the FalseValue. Thus: =IF([SomeDate]="",1/1/1800,[SomeDate]) will return 1/1/1800 if the date is blank and the date itself if not. So, using this formula, if the welder missed an exam, the returned exam date will be far in the past. It would be nice if we could take such a formula and make it into a reusable function. Alas, here is a calculated field serious shortcoming: You cannot write subs and functions!! Aha, but we can use interim calculated fields! So let’s create 3 calculated fields as follows: 1: c_DateTestA as a calculated field of the date type, with the formula:  IF([Date_TestA]="",1/1/1800,[Date_TestA]) 2: c_DateTestB as a calculated field of the date type, with the formula:  IF([Date_TestB]="",1/1/1800,[Date_TestB]) 3: c_DateEyeExam as a calculated field of the date type, with the formula:  IF([Date_EyeExam]="",1/1/1800,[Date_EyeExam]) And now use these to get c_MinDate. This is again a calculated field of type date with the formula: MIN(c_DateTestA, cDateTestB, c_DateEyeExam) Note that I missed the square parentheses. In “properly named fields – where there are no embedded spaces, we don’t need the square parentheses. I actually strongly recommend using underscores in place of spaces in all the field names in your lists. Among other things, it makes using CAML much simpler. Now, we still need to apply the KPI to this minimal date. I am going to use the available KPI graphics that come with SharePoint and are always available in your 12 hive. "/_layouts/images/kpidefault-2.gif" is the Red KPI "/_layouts/images/kpidefault-1.gif" is the Yellow KPI "/_layouts/images/kpidefault-0.gif" is the Green KPI And here is the nested IF formula that will do the trick: =IF(c_MinDate<=Today,"/_layouts/images/kpidefault-2.gif", IF(cMinDate<Today+90,"/_layouts/images/kpidefault-1.gif","/_layouts/images/kpidefault-0.gif")) Nice! BUT when I tested, it did not work! This is Idiosyncrasy #2: A calculated field based on a calculated field based on a calculated field does not work. You have to stop at two levels! Back to the drawing board: We have to reduce by one level. How? We’ll eliminate the c_DateX items in the formula and replace them with the proper IF formulae. Notice that this needs to be done with precision. You are much better off in doing it in your favorite line editor, than inside the cramped space that SharePoint gives you. So here is the result: MIN(IF([Date_TestA]="",1/1/1800,[ Date_TestA]), IF([Date_TestB]="",1/1/1800,[ Date_TestB]), 1/1/1800), IF([Date_EyeExam]="",1/1/1800,[Date_EyeExam])) Note that I bolded the parentheses and painted them red. They have to match for this formula to work. Now we can leave the KPI formula as is and test again. This time with SUCCESS! Conclusion: build the inner functions first, and then embed them inside the outer formulae. Do this as long as necessary. Use your favorite line editor. Limit yourself to 2 levels. That’s all folks! Almost! As soon as I finished doing all of the above, my users added yet another level of complexity. They added another test, a test that must be passed, but never expires and asked for yet another KPI, this time in Black to denote that any test is not just past due, but altogether missing. I just finished this. Let’s hope it ends here! And OH, the formula  =IF(c_MinDate<=Today,"/_layouts/images/kpidefault-2.gif",IF(cMinDate<Today+90,"/_layouts/images/kpidefault-1.gif","/_layouts/images/kpidefault-0.gif")) Deals with “Today” and this is a subject deserving a discussion of its own!  That’s all folks?! (and this time I mean it)

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  • Simplifying Human Capital Management with Mobile Applications

    - by HCM-Oracle
    By Aaron Green If you're starting to think 'mobility' is a recurring theme in your reading, you'd be right. For those who haven't started to build organisational capabilities to leverage it, it's fair to say you're late to the party. The good news: better late than never. Research firm eMarketer says the worldwide smartphone audience will total 1.75 billion this year, while communications technology and services provider Ericsson suggests smartphones will triple to 5.6 billion globally by 2019. It should be no surprise, smart phone adoption is reaching the farthest corners of the globe; the subsequent impact of enterprise applications enabled by these devices is driving business performance improvement and will continue to do so. Companies using advanced workforce analytics can add significantly to the bottom line, while impacting customer satisfaction, quality and productivity. It's a statement that makes most business leaders sit forward in their chairs. Achieving these three standards is like sipping The Golden Elixir for the business world. No-one would argue their importance. So what are 'advanced workforce analytics?' Simply, they're unprecedented access to workforce trends and performance markers. Many are made possible by a mobile world and the enterprise applications that come with it on smart devices. Some refer to it as 'the consumerisation of IT'. As this phenomenon has matured and become more widely appreciated it has impacted the spectrum of functional units within an enterprise differently, but powerfully. Whether it's sales, HR, marketing, IT, or operations, all have benefited from a more mobile approach. It has been the catalyst for improvement in, and management of, the employee experience. The net result of which is happier customers. The obvious benefits but the lesser realised impact Most people understand that mobility allows for greater efficiency and productivity, collaboration and flexibility, but how that translates into business outcomes within the various functional groups is lesser known. In actuality mobility has helped galvanise partnerships between cross-functional groups within the enterprise. Where in some quarters it was once feared mobility could fragment a workforce, its rallying cry of support is coming from what you might describe as an unlikely source - HR. As the bedrock of an enterprise, it is conceivable HR might contemplate the possible negative impact of a mobile workforce that no-longer sits in an office, at the same desks every day. After all, who would know what they were doing or saying? How would they collaborate? It's reasonable to see why HR might have a legitimate claim to try and retain as much 'perceived control' as possible. The reality however is mobility has emancipated human capital and its management. Mobility and enterprise applications are expediting decision making. Google calls it Zero Moment of Truth, or ZMOT. It enables smoother operation and can contribute to faster growth. From a collaborative perspective, with the growing use of enterprise social media, which in many cases is being driven by HR, workforce planning and the tangible impact of change is much easier to map. This in turn provides a platform from which individuals and teams can thrive. With more agility and ability to anticipate, staff satisfaction and retention is higher, and real time feedback constant. The management team can save time, energy and costs with more accurate data, which is then intelligently applied across the workforce to truly engage with staff, customers and partners. From a human capital management (HCM) perspective, mobility can help you close the loop on true talent management. It can enhance what managers can offer and what employees can provide in return. It can create nested relationships and powerful partnerships. IT and HR - partners and stewards of mobility One effect of enterprise mobility is an evolution in the nature of the relationship between HR and IT from one of service provision to partnership. The reason for the dynamic shift is largely due to the 'bring your own device' (BYOD) movement, which is transitioning to a 'bring your own application' (BYOA) scenario. As enterprise technology has in some ways reverse-engineered its solutions to help manage this situation, the partnership between IT (the functional owner) and HR (the strategic enabler) is deeply entrenched. And it has to be. The CIO and the HR leader are faced with compliance and regulatory issues and concerns around information security and personal privacy on a daily basis, complicated by global reach and varied domestic legislation. There are tens of thousands of new mobile apps entering the market each month and, unlike many consumer applications which get downloaded but are often never opened again after initial perusal, enterprise applications are being relied upon by functional groups, not least by HR to enhance people management. It requires a systematic approach across all applications in use within the enterprise in order to ensure they're used to best effect. No turning back, and no desire to With real time analytics on performance and the ability for immediate feedback, there is no turning back for managers. In my experience with Oracle, our customers' operational efficiency is at record levels. It's clear as a result of the combination of individual KPIs and organisational goals, CIOs have been able to give HR leaders the ability to build predictive models that feed into an enterprise organisations' evolving strategy. It also helps them ensure regulatory compliance much more easily. Once an arduous task, with mobile enabled automation and quality data, compliance is simpler. Their world has changed for the better. For the CIO, mobility also assists them to optimise performance. While it doesn't come without challenges, mobile-enabled applications and the native experience users have with them means employees don't need high-level technical expertise to train users. It reduces the training and engagement required from the IT team so they can focus on other things that deliver value to the bottom line; all the while lowering the cost of assets and related maintenance work by simplifying processes. Rewards of a mobile enterprise outweigh risks With mobile tools allowing us to increasingly integrate our personal and professional lives, terms like "office hours" are becoming irrelevant, so work/life balance is a cultural must. Enterprises are expected to offer tools that enable workers to access information from anywhere, at any time, from any device. Employees want simplicity and convenience but it doesn't stop at private enterprise. This is a societal shift. Governments, which traditionally have been known to be slower to adopt newer technology, are also offering support for local businesses to go mobile. Several state government websites have advice on how to create mobile apps and more. And as recently as last week the Victorian Minister for Technology Gordon Rich-Phillips unveiled his State government's ICT roadmap for the next two years, which details an increased use of the public cloud, as well as mobile communications, and improved access to online data-sets. Tech giants are investing significantly in solutions designed to simplify mobile deployment and enablement. The mobility trend is creating a wave of change in the industry and driving transformation in the enterprise. If you're not on that wave, the business risk continues to rise as your competitiveness drops. Aaron is the Vice President of HCM Strategy at Oracle Corporation where he is responsible for researching and identifying emerging trends in the practice of Human Resources and works to deliver industry-leading technology solutions. Other responsibilities include, ownership of Oracle's innovative HCM solutions across JAPAC and enabling organisations to transform and modernise their workforce tools. Follow him on Twitter @aaronjgreen

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  • Do you have suggestions for these assembly mnemonics?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • Help with refactoring PHP code

    - by Richard Knop
    I had some troubles implementing Lawler's algorithm but thanks to SO and a bounty of 200 reputation I finally managed to write a working implementation: http://stackoverflow.com/questions/2466928/lawlers-algorithm-implementation-assistance I feel like I'm using too many variables and loops there though so I am trying to refactor the code. It should be simpler and shorter yet remain readable. Does it make sense to make a class for this? Any advice or even help with refactoring this piece of code is welcomed: <?php /* * @name Lawler's algorithm PHP implementation * @desc This algorithm calculates an optimal schedule of jobs to be * processed on a single machine (in reversed order) while taking * into consideration any precedence constraints. * @author Richard Knop * */ $jobs = array(1 => array('processingTime' => 2, 'dueDate' => 3), 2 => array('processingTime' => 3, 'dueDate' => 15), 3 => array('processingTime' => 4, 'dueDate' => 9), 4 => array('processingTime' => 3, 'dueDate' => 16), 5 => array('processingTime' => 5, 'dueDate' => 12), 6 => array('processingTime' => 7, 'dueDate' => 20), 7 => array('processingTime' => 5, 'dueDate' => 27), 8 => array('processingTime' => 6, 'dueDate' => 40), 9 => array('processingTime' => 3, 'dueDate' => 10)); // precedence constrainst, i.e job 2 must be completed before job 5 etc $successors = array(2=>5, 7=>9); $n = count($jobs); $optimalSchedule = array(); for ($i = $n; $i >= 1; $i--) { // jobs not required to precede any other job $arr = array(); foreach ($jobs as $k => $v) { if (false === array_key_exists($k, $successors)) { $arr[] = $k; } } // calculate total processing time $totalProcessingTime = 0; foreach ($jobs as $k => $v) { if (true === array_key_exists($k, $arr)) { $totalProcessingTime += $v['processingTime']; } } // find the job that will go to the end of the optimal schedule array $min = null; $x = 0; $lastKey = null; foreach($arr as $k) { $x = $totalProcessingTime - $jobs[$k]['dueDate']; if (null === $min || $x < $min) { $min = $x; $lastKey = $k; } } // add the job to the optimal schedule array $optimalSchedule[$lastKey] = $jobs[$lastKey]; // remove job from the jobs array unset($jobs[$lastKey]); // remove precedence constraint from the successors array if needed if (true === in_array($lastKey, $successors)) { foreach ($successors as $k => $v) { if ($lastKey === $v) { unset($successors[$k]); } } } } // reverse the optimal schedule array and preserve keys $optimalSchedule = array_reverse($optimalSchedule, true); // add tardiness to the array $i = 0; foreach ($optimalSchedule as $k => $v) { $optimalSchedule[$k]['tardiness'] = 0; $j = 0; foreach ($optimalSchedule as $k2 => $v2) { if ($j <= $i) { $optimalSchedule[$k]['tardiness'] += $v2['processingTime']; } $j++; } $i++; } echo '<pre>'; print_r($optimalSchedule); echo '</pre>';

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  • C++ - Unwanted characters printed in output file.

    - by Gabe
    This is the last part of the program I am working on. I want to output a tabular list of songs to cout. And then I want to output a specially formatted list of song information into fout (which will be used as an input file later on). Printing to cout works great. The problem is that tons of extra character are added when printing to fout. Any ideas? Here's the code: void Playlist::printFile(ofstream &fout, LinkedList<Playlist> &allPlaylists, LinkedList<Songs*> &library) { fout.open("music.txt"); if(fout.fail()) { cout << "Output file failed. Information was not saved." << endl << endl; } else { if(library.size() > 0) fout << "LIBRARY" << endl; for(int i = 0; i < library.size(); i++) // For Loop - "Incremrenting i"-Loop to go through library and print song information. { fout << library.at(i)->getSongName() << endl; // Prints song name. fout << library.at(i)->getArtistName() << endl; // Prints artist name. fout << library.at(i)->getAlbumName() << endl; // Prints album name. fout << library.at(i)->getPlayTime() << " " << library.at(i)->getYear() << " "; fout << library.at(i)->getStarRating() << " " << library.at(i)->getSongGenre() << endl; } if(allPlaylists.size() <= 0) fout << endl; else if(allPlaylists.size() > 0) { int j; for(j = 0; j < allPlaylists.size(); j++) // Loops through all playlists. { fout << "xxxxx" << endl; fout << allPlaylists.at(j).getPlaylistName() << endl; for(int i = 0; i < allPlaylists.at(j).listSongs.size(); i++) { fout << allPlaylists.at(j).listSongs.at(i)->getSongName(); fout << endl; fout << allPlaylists.at(j).listSongs.at(i)->getArtistName(); fout << endl; } } fout << endl; } } } Here's a sample of the output to music.txt (fout): LIBRARY sadljkhfds dfgkjh dfkgh 3 3333 3 Rap sdlkhs kjshdfkh sdkjfhsdf 3 33333 3 Rap xxxxx PayröÈöè÷÷(÷H÷h÷÷¨÷È÷èøø(øHøhøø¨øÈøèùù(ùHùhùù¨ùÈùèúú(úHúhúú¨úÈúèûû(ûHûhûû¨ûÈûèüü(üHühüü¨üÈüèýý(ýHýhý ! sdkjfhsdf!õüöýÄõ¼5! sadljkhfds!þõÜö|ö\ þx þ  þÈ þð ÿ ÿ@ ÿh ÿ ÿ¸ ÿà 0 X ¨ Ð ø enter code here enter code here

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  • trie reg exp parse step over char and continue

    - by forest.peterson
    Setup: 1) a string trie database formed from linked nodes and a vector array linking to the next node terminating in a leaf, 2) a recursive regular expression function that if A) char '*' continues down all paths until string length limit is reached, then continues down remaining string paths if valid, and B) char '?' continues down all paths for 1 char and then continues down remaining string paths if valid. 3) after reg expression the candidate strings are measured for edit distance against the 'try' string. Problem: the reg expression works fine for adding chars or swapping ? for a char but if the remaining string has an error then there is not a valid path to a terminating leaf; making the matching function redundant. I tried adding a 'step-over' ? char if the end of the node vector was reached and then followed every path of that node - allowing this step-over only once; resulted in a memory exception; I cannot find logically why it is accessing the vector out of range - bactracking? Questions: 1) how can the regular expression step over an invalid char and continue with the path? 2) why is swapping the 'sticking' char for '?' resulting in an overflow? Function: void Ontology::matchRegExpHelper(nodeT *w, string inWild, Set<string> &matchSet, string out, int level, int pos, int stepover) { if (inWild=="") { matchSet.add(out); } else { if (w->alpha.size() == pos) { int testLength = out.length() + inWild.length(); if (stepover == 0 && matchSet.size() == 0 && out.length() > 8 && testLength == tokenLength) {//candidate generator inWild[0] = '?'; matchRegExpHelper(w, inWild, matchSet, out, level, 0, stepover+1); } else return; //giveup on this path } if (inWild[0] == '?' || (inWild[0] == '*' && (out.length() + inWild.length() ) == level ) ) { //wild matchRegExpHelper(w->alpha[pos].next, inWild.substr(1), matchSet, out+w->alpha[pos].letter, level, 0, stepover);//follow path -> if ontology is full, treat '*' like a '?' } else if (inWild[0] == '*') matchRegExpHelper(w->alpha[pos].next, '*'+inWild.substr(1), matchSet, out+w->alpha[pos].letter, level, 0, stepover); //keep adding chars if (inWild[0] == w->alpha[pos].letter) //follow self matchRegExpHelper(w->alpha[pos].next, inWild.substr(1), matchSet, out+w->alpha[pos].letter, level, 0, stepover); //follow char matchRegExpHelper(w, inWild, matchSet, out, level, pos+1, stepover);//check next path } } Error Message: +str "Attempt to access index 1 in a vector of size 1." std::basic_string<char,std::char_traits<char>,std::allocator<char> > +err {msg="Attempt to access index 1 in a vector of size 1." } ErrorException Note: this function works fine for hundreds of test strings with '*' wilds if the extra stepover gate is not used Semi-Solved: I place a pos < w->alpha.size() condition on each path that calls w->alpha[pos]... - this prevented the backtrack calls from attempting to access the vector with an out of bounds index value. Still have other issues to work out - it loops infinitely adding the ? and backtracking to remove it, then repeat. But, moving forward now. Revised question: why during backtracking is the position index accumulating and/or not deincrementing - so at somepoint it calls w->alpha[pos]... with an invalid position that is either remaining from the next node or somehow incremented pos+1 when passing upward?

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  • How do I learn algorithms?

    - by Panthe
    Brief History: Just graduated high school, learned a bit of python and C++, have no friends with any helpful computer knowledge at all. Out of anyone i met in my school years I was probably the biggest nerd, but no one really knew. I consider my self to have a vast amount of knowledge on computers and tech then the average person. built/fixed tons of computers, and ability to troubleshoot pretty much any problem I came across. Now that high school is over, Ive really been thinking about my career. Loving, living computers for the past 15 years of my life I decided to take my ability's and try to learn computer programming, why I didn't start earlier I don't know, seems to be big mistake on my part... Doing some research I concluded that Python was the first programming language I should learn, since it was high level and easier to understand then C++ and Java. I also knew that to become good at what I did I needed to know more then just 2 or 3 languages, which didn't seem like a big problem considering once I learned the way Python worked, mainly syntax changed, and the rest would come naturally. I watched a couple of youtube videos, downloaded some book pdf's and snooped around from some tutorials here and there to get the hang of what to do. A two solid weeks had passed of trying to understand the syntax, create small programs that used the basic functions and understanding how it worked, I think i have got the hang of it. It breaks down into what ive been dealing with all this time (although i kinda knew) is that, input,output, loops, functions and other things derived from 0's and 1's storing data and recalling it, ect. (A VERY BASIC IDEA). Ive been able to create small programs, Hangman, file storing, temperature conversion, Caeser Cipher decode/encoding, Fibonacci Sequence and more, which i can create and understand how each work. Being 2 weeks into this, I have learned alot. Nothing at all compared to what i should be lear ning in the years to come if i get a grip on what I'm doing. While doing these programs I wont stop untill I've done doing a practice problem on a book, which embarresing enough will take me a couple hour depending on the complexity of it. I absolutly will not put aside the challenge until its complete, WHICH CAN BE EXTREMELY DRAINING, ive tried most problems without cheating and reached success, which makes me feel extremely proud of my self after completing something after much trial and error. After all this I have met the demon, alogrithm's which seem to be key to effiecent code. I cant seem to rap my head around some of the computer codes people put out there using numbers, and sometimes even basic functions, I have been able to understand them after a while but i know there are alot more complex things to come, considering my self smart, functions that require complex codes, actually hurt my brain. NOTHING EVER IN LIFE HURT MY BRAIN....... not even math classes in highschool, trying to understand some of the stuff people put out there makes me feel like i have a mental disadvantage lol... i still walk forward though, crossing my fingers that the understanding will come with time. Sorry if is this is long i just wish someone takes all these things into consideration when answering my question. even through all these downsides im still pushing through and continuing to try and get good at this, i know reading these tutorials wont make me any good unless i can become creative and make my own, understand other peoples programs, so this leads me to the simple question i could have asked in the beginning..... WHERE IN THE WORLD DO I START ? Ive been trying to find out how to understand some of the open source projects, how i can work with experianced coders to learn from them and help them, but i dont think thats even possible by the way how far people's knowledge is compared to me, i have no freinds who i can learn from, can someone help me and guide me into the right direction.. i have a huge motivation to get good at coding, anything information would be extremely helpful

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