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  • Abstract Data Type: Any1 can help me this? thanks..

    - by Aga Hibaya
    Objectives: Implement the Abstract Data Type (ADT) List using dynamically allocated arrays and structures. Description A LIST is an ordered collection of items where items may be inserted anywhere in the list. Implement a LIST using an array as follows: struct list { int *items; // pointer to the array int size; // actual size of the array int count; // number of items in the array }; typedef struct list *List; // pointer to the structure Implement the following functions: a) List newList(int size); - will create a new List and return its pointer. Allocate space for the structure, allocate space for the array, then initialize size and count, return the pointer. b) void isEmpty(List list); c) void display(List list); d) int contains(List list, int item); e) void remove(List list, int i) ; f) void insertAfter(List list,int item, int i); g) void addEnd(List list,int item) - add item at the end of the list – simply store the data at position count, then increment count. If the array is full, allocate an array twice as big as the original. count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 addEnd(list,40) will result to count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 40 h) void addFront(List list,int item) - shift all elements to the right so that the item can be placed at position 0, then increment count. Bonus: if the array is full, allocate an array twice as big as the original. count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 addFront(list,40) will result to count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 i) void removeFront(List list) - shift all elements to the left and decrement count; count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 removeFront(list) will result to count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 5 10 15 20 30 j) void remove(List list,int item) - get the index of the item in the list and then shift all elements to the count = 6 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 10 15 20 30 remove(list,10) will result to count = 5 size = 10 0 1 2 3 4 5 6 7 8 9 40 5 15 20 30 Remarks

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  • How do I get the next token in a Cstring if I want to use it as an int? (c++)

    - by Van
    My objective is to take directions from a user and eventually a text file to move a robot. The catch is that I must use Cstrings(such as char word[];) rather than the std::string and tokenize them for use. the code looks like this: void Navigator::manualDrive() { char uinput[1]; char delim[] = " "; char *token; cout << "Enter your directions below: \n"; cin.ignore(); cin.getline (uinput, 256); token=strtok(uinput, delim); if(token == "forward") { int inches; inches=token+1; travel(inches); } } I've never used Cstrings I've never tokenized anything before, and I don't know how to write this. Our T.A.'s expect us to google and find all the answers because they are aware we've never been taught these methods. Everyone in my lab is having much more trouble than usual. I don't know the code to write but I know what I want my program to do. I want it to execute like this: 1) Ask for directions. 2) cin.getline the users input 3) tokenize the inputed string 4) if the first word token == "forward" move to the next token and find out how many inches to move forward then move forward 5) else if the first token == "turn" move to the next token. if the next token == "left" move to the next token and find out how many degrees to turn left I will have to do this for forward x, backward x, turn left x, turn right x, and stop(where x is in inches or degrees). I already wrote functions that tell the robot how to move forward an inch and turn in degrees. I just need to know how to convert the inputted strings to all lowercase letters and move from token to token and convert or extract the numbers from the string to use them as integers. If all is not clear you can read my lab write up at this link: http://www.cs.utk.edu/~cs102/robot_labs/Lab9.html If anything is unclear please let me know, and I will clarify as best I can.

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  • Strange behavior of move with strings

    - by Umair Ahmed
    I am testing some enhanced string related functions with which I am trying to use move as a way to copy strings around for faster, more efficient use without delving into pointers. While testing a function for making a delimited string from a TStringList, I encountered a strange issue. The compiler referenced the bytes contained through the index when it was empty and when a string was added to it through move, index referenced the characters contained. Here is a small downsized barebone code sample:- unit UI; interface uses System.SysUtils, System.Types, System.UITypes, System.Rtti, System.Classes, System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs, FMX.Layouts, FMX.Memo; type TForm1 = class(TForm) Results: TMemo; procedure FormCreate(Sender: TObject); end; var Form1: TForm1; implementation {$R *.fmx} function StringListToDelimitedString ( const AStringList: TStringList; const ADelimiter: String ): String; var Str : String; Temp1 : NativeInt; Temp2 : NativeInt; DelimiterSize : Byte; begin Result := ' '; Temp1 := 0; DelimiterSize := Length ( ADelimiter ) * 2; for Str in AStringList do Temp1 := Temp1 + Length ( Str ); SetLength ( Result, Temp1 ); Temp1 := 1; for Str in AStringList do begin Temp2 := Length ( Str ) * 2; // Here Index references bytes in Result Move ( Str [1], Result [Temp1], Temp2 ); // From here the index seems to address characters instead of bytes in Result Temp1 := Temp1 + Temp2; Move ( ADelimiter [1], Result [Temp1], DelimiterSize ); Temp1 := Temp1 + DelimiterSize; end; end; procedure TForm1.FormCreate(Sender: TObject); var StrList : TStringList; Str : String; begin // Test 1 : StringListToDelimitedString StrList := TStringList.Create; Str := ''; StrList.Add ( 'Hello1' ); StrList.Add ( 'Hello2' ); StrList.Add ( 'Hello3' ); StrList.Add ( 'Hello4' ); Str := StringListToDelimitedString ( StrList, ';' ); Results.Lines.Add ( Str ); StrList.Free; end; end. Please devise a solution and if possible, some explanation. Alternatives are welcome too.

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  • Establishing a tcp connection from within a DLL

    - by Nicholas Hollander
    I'm trying to write a piece of code that will allow me to establish a TCP connection from within a DLL file. Here's my situation: I have a ruby application that needs to be able to send and receive data over a socket, but I can not access the native ruby socket methods because of the environment in which it will be running. I can however access a DLL file and run the functions within that, so I figured I would create a wrapper for winsock. Unfortunately, attempting to take a piece of code that should connect to a TCP socket in a normal C++ application throws a slew of LNK2019 errors that I can not for the life of me resolve. This is the method I'm using to connect: //Socket variable SOCKET s; //Establishes a connection to the server int server_connect(char* addr, int port) { //Start up Winsock WSADATA wsadata; int error = WSAStartup(0x0202, &wsadata); //Check if something happened if (error) return -1; //Verify Winock version if (wsadata.wVersion != 0x0202) { //Clean up and close WSACleanup(); return -2; } //Get the information needed to finalize a socket SOCKADDR_IN target; target.sin_family = AF_INET; //Address family internet target.sin_port = _WINSOCKAPI_::htons(port); //Port # target.sin_addr.s_addr = inet_addr(addr); //Create the socket s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (s == INVALID_SOCKET) { return -3; } //Try connecting if (connect(s, (SOCKADDR *)&target, sizeof(target)) == SOCKET_ERROR) { //Failed to connect return -4; } else { //Success return 1; } } The exact errors that I'm receiving are: Error 1 error LNK2019: unresolved external symbol _closesocket@4 referenced in function _server_disconnect [Project Path] Error 2 error LNK2019: unresolved external symbol _connect@12 referenced in function _server_connect [Project Path] Error 3 error LNK2019: unresolved external symbol _htons@4 referenced in function _server_connect [Project Path] Error 4 error LNK2019: unresolved external symbol _inet_addr@4 referenced in function _server_connect [Project Path] Error 5 error LNK2019: unresolved external symbol _socket@12 referenced in function _server_connect [Project Path] Error 6 error LNK2019: unresolved external symbol _WSAStartup@8 referenced in function _server_connect [Project Path] Error 7 error LNK2019: unresolved external symbol _WSACleanup@0 referenced in function _server_connect [Project Path] Error 8 error LNK1120: 7 unresolved externals [Project Path] 1 1 Many thanks!

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  • How to apply or chain multiple matching templates in XSLT?

    - by Ignatius
    I am working on a stylesheet employing many templates with match attributes: <xsl:template match="//one" priority="0.7"> <xsl:param name="input" select="."/> <xsl:value-of select="util:uppercase($input)"/> <xsl:next-match /> </xsl:template> <xsl:template match="/stuff/one"> <xsl:param name="input" select="."/> <xsl:value-of select="util:add-period($input)"/> </xsl:template> <xsl:function name="util:uppercase"> <xsl:param name="input"/> <xsl:value-of select="upper-case($input)"/> </xsl:function> <xsl:function name="util:add-period"> <xsl:param name="input"/> <xsl:value-of select="concat($input,'.')"/> </xsl:function> What I would like to do is be able to 'chain' the two functions above, so that an input of 'string' would be rendered in the output as 'STRING.' (with the period.) I would like to do this in such a way that doesn't require knowledge of other templates in any other template. So, for instance, I would like to be able to add a "util:add-colon" method without having to open up the hood and monkey with the existing templates. I was playing around with the <xsl:next-match/> instruction to accomplish this. Adding it to the first template above does of course invoke both util:uppercase and util:add-period, but the output is an aggregation of each template output (i.e. 'STRINGstring.') It seems like there should be an elegant way to chain any number of templates together using something like <xsl:next-match/>, but have the output of each template feed the input of the next one in the chain. Am I overlooking something obvious?

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  • Difficulty adding widgets to django form.

    - by codingJoe
    I have a django app that tracks activities that can benefit a classroom. Using the django examples, I was able to build a form to enter this data. But when I try to add widgets to that form, things get tricky. What I want is a calendar widget that lets the user enter the 'activity_date' field using a widget. If I use Admin interface. The AdminDateWidget works fine. however. This particular user isn't allowed access to the admin interface so I need a different way to present this widget. Also I couldn't figure out how to make the bring the admin widget over into non-admin pages. So I tried a custom widget. This is the first custom widget I've built, so I'm not quite sure what is supposed to be going on here. Any Expert Advice? How do I get my date widget to work? # The Model class Activity(models.Model): activity_date = models.DateField() activity_type = models.CharField(max_length=50, choices=ACTIVITY_TYPES) activity_description = models.CharField(max_length=200) activity_duration= models.DecimalField(decimal_places=2, max_digits=4) est_attendance = models.IntegerField("Estimated attendance") # The Form class ActivityForm(forms.ModelForm): # The following line causes lockup if enabled. # With the DateTimeWidget removed, the form functions correctly except that there is no widget. #activity_date = forms.DateField(label=_('Date'), widget=DateTimeWidget) ##!!! Point of Error !!! class Meta: model = Activity fields = ('activity_date', 'activity_type', 'activity_description', 'activity_duration', 'est_attendance') def __init__(self, *args, **kwargs): super(ActivityForm, self).__init__(*args, **kwargs) instance = getattr(self, 'instance', None) edit_aid = kwargs.get('edit_aid', False) # On a different approach, the following also didn't work. #self.fields['activity_date'].widget = widgets.AdminDateWidget() # The Widget # Example referenced: http://djangosnippets.org/snippets/391/ calbtn = u""" <button id="calendar-trigger">...</button> <img src="%s/site_media/images/icon_calendar.gif" alt="calendar" id="%s_btn" style="cursor: pointer; border: 1px solid #8888aa;" title="Select date and time" onmouseover="this.style.background='#444444';" onmouseout="this.style.background=''" /> <script type="text/javascript"> Calendar.setup({ trigger : "calendar-trigger", inputField : "%s" }); </script>""" class DateTimeWidget(forms.widgets.TextInput): dformat = '%Y-%m-%d %H:%M' def render(self, name, value, attrs=None): print "DTWgt render name=%s, value=%s" % name, value if value is None: value = '' final_attrs = self.build_attrs(attrs, type=self.input_type, name=name) if value != '': try: final_attrs['value'] = \ force_unicode(value.strftime(self.dformat)) except: final_attrs['value'] = \ force_unicode(value) if not final_attrs.has_key('id'): final_attrs['id'] = u'%s_id' % (name) id = final_attrs['id'] jsdformat = self.dformat #.replace('%', '%%') cal = calbtn % (settings.MEDIA_URL, id, id, jsdformat, id) a = u'<input%s />%s' % (forms.util.flatatt(final_attrs), cal) print "render return %s " % a return mark_safe(a) def value_from_datadict(self, data, files, name): print "DTWgt value_from_datadict" dtf = forms.fields.DEFAULT_DATETIME_INPUT_FORMATS empty_values = forms.fields.EMPTY_VALUES value = data.get(name, None) if value in empty_values: return None if isinstance(value, datetime.datetime): return value if isinstance(value, datetime.date): return datetime.datetime(value.year, value.month, value.day) for format in dtf: try: return datetime.datetime(*time.strptime(value, format)[:6]) except ValueError: continue return None

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  • USB windows xp final USB access issues

    - by Lex Dean
    I basically understand you C++ people, Please do not get distracted because I'm writing in Delphi. I have a stable USB Listing method that accesses all my USB devices I get the devicepath, and this structure: TSPDevInfoData = packed record Size: DWORD; ClassGuid: TGUID; DevInst: DWORD; // DEVINST handle Reserved: DWord; end; I get my ProductID and VenderID successfully from my DevicePath Lists all USB devices connected to the computer at the time That enables me to access the registry data to each device in a stable way. What I'm lacking is a little direction Is friendly name able to be written inside the connected USB Micro chips by the firmware programmer? (I'm thinking of this to identify the device even further, or is this to help identify Bulk data transfer devices like memory sticks and camera's) Can I use SPDRP_REMOVAL_POLICY_OVERRIDE to some how reset these polices What else can I do with the registry details. Identifying when some one unplugs a device The program is using (in windows XP standard) I used a documented windows event that did not respond. Can I read a registry value to identify if its still connected? using CreateFileA (DevicePath) to send and receive data I have read when some one unplugs in the middle of a data transfer its difficult clearing resources. what can IoCreateDevice do for me and how does one use it for that task This two way point of connection status and system lock up situations is very concerning. Has some one read anything about this subject recently? My objectives are to 1. list connected USB devices identify a in development Micro Controller from everything else send and receive data in a stable and fast way to the limits of the controller No lock up's transferring data Note I'm not using any service packs I understand everything USB is in ANSI when windows xp is not and .Net is all about ANSI (what a waste of memory) I plan to continue this project into a .net at a later date as an addition. MSDN gives me Structures and Functions and what should link to what ok but say little to what they get used for. What is available in my language Delphi is way over priced that it needs a major price drop.

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  • How do I recover from an unchecked exception?

    - by erickson
    Unchecked exceptions are alright if you want to handle every failure the same way, for example by logging it and skipping to the next request, displaying a message to the user and handling the next event, etc. If this is my use case, all I have to do is catch some general exception type at a high level in my system, and handle everything the same way. But I want to recover from specific problems, and I'm not sure the best way to approach it with unchecked exceptions. Here is a concrete example. Suppose I have a web application, built using Struts2 and Hibernate. If an exception bubbles up to my "action", I log it, and display a pretty apology to the user. But one of the functions of my web application is creating new user accounts, that require a unique user name. If a user picks a name that already exists, Hibernate throws an org.hibernate.exception.ConstraintViolationException (an unchecked exception) down in the guts of my system. I'd really like to recover from this particular problem by asking the user to choose another user name, rather than giving them the same "we logged your problem but for now you're hosed" message. Here are a few points to consider: There a lot of people creating accounts simultaneously. I don't want to lock the whole user table between a "SELECT" to see if the name exists and an "INSERT" if it doesn't. In the case of relational databases, there might be some tricks to work around this, but what I'm really interested in is the general case where pre-checking for an exception won't work because of a fundamental race condition. Same thing could apply to looking for a file on the file system, etc. Given my CTO's propensity for drive-by management induced by reading technology columns in "Inc.", I need a layer of indirection around the persistence mechanism so that I can throw out Hibernate and use Kodo, or whatever, without changing anything except the lowest layer of persistence code. As a matter of fact, there are several such layers of abstraction in my system. How can I prevent them from leaking in spite of unchecked exceptions? One of the declaimed weaknesses of checked exceptions is having to "handle" them in every call on the stack—either by declaring that a calling method throws them, or by catching them and handling them. Handling them often means wrapping them in another checked exception of a type appropriate to the level of abstraction. So, for example, in checked-exception land, a file-system–based implementation of my UserRegistry might catch IOException, while a database implementation would catch SQLException, but both would throw a UserNotFoundException that hides the underlying implementation. How do I take advantage of unchecked exceptions, sparing myself of the burden of this wrapping at each layer, without leaking implementation details?

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  • C++ Class Templates (Queue of a class)

    - by Dalton Conley
    Ok, so I have my basic linked Queue class with basic functions such as front(), empty() etc.. and I have transformed it into a template. Now, I also have a class called Student. Which holds 2 values: Student name and Student Id. I can print out a student with the following code.. Student me("My Name", 2); cout << me << endl; Here is my display function for student: void display(ostream &out) const { out << "Student Name: " << name << "\tStudent Id: " << id << "\tAddress: " << this << endl; } Now it works fine, you can see the basic output. Now I'm declaring a queue like so.. Queue<Student> qstu; Storing data in this queue is fine, I can add new values and such.. now what I'm trying to do is print out my whole queue of students with: cout << qstu << endl; But its simply returning an address.. here is my display function for queues. void display(ostream & out) const { NodePointer ptr; ptr = myFront; while(ptr != NULL) { out << ptr->data << " "; ptr = ptr->next; } out << endl; } Now, based on this, I assume ptr-data is a Student type and I would assume this would work, but it doesn't. Is there something I'm missing? Also, when I Try: ptr->data.display(out); (Making the assumtion ptr-data is of type student, it does not work which tells me I am doing something wrong. Help on this would be much appreciated!

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  • how i can use SAX parser

    - by moustafa
    This is what the result should look like when i parse it through a SAX parser http://img13.imageshack.us/img13/6950/75914446.jpg This is the XML source code from which i need to generate the display: <orders> <order> <count>37</count> <price>49.99</price> <book> <isbn>0130897930</isbn> <title>Core Web Programming Second Edition</title> <authors> <count>2</count> <author>Marty Hall</author> <author>Larry Brown</author> </authors> </book> </order> <order> <count>1</count> <price>9.95</price> <yacht> <manufacturer>Luxury Yachts, Inc.</manufacturer> <model>M-1</model> <standardFeatures oars="plastic" lifeVests="none">false</standardFeatures> </yacht> </order> <order> <count>3</count> <price>22.22</price> <book> <isbn>B000059Z4H</isbn> <title>Harry Potter and the Order of the Phoenix</title> <authors> <count>1</count> <author>J.K. Rowling</author> </authors> </book> </order> i really have no clue how to code the functions but i have just set up the parser $xmlParser = xml_parser_create("UTF-8"); xml_parser_set_option($xmlParser, XML_OPTION_CASE_FOLDING, false); xml_set_element_handler($xmlParser, 'startElement', 'endElement'); xml_set_character_data_handler($xmlParser, 'HandleCharacterData'); $fileName = 'orders.xml'; if (!($fp = fopen($fileName, 'r'))){ die('Cannot open the XML file: ' . $fileName); } while ($data = fread($fp, 4096)){ $parsedOkay = xml_parse($xmlParser, $data, feof($fp)); if (!$parsedOkay){ print ("There was an error or the parser was finished."); break; } } xml_parser_free($xmlParser); function startElement($xmlParser, $name, $attribs) { } function endElement($parser, $name) { } function HandleCharacterData($parser, $data) { }

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  • File sizing issue in DOS/FAT

    - by Heather
    I've been tasked with writing a data collection program for a Unitech HT630, which runs a proprietary DOS operating system that can run executables compiled for 16-bit MS DOS with some restrictions. I'm using the Digital Mars C/C++ compiler, which is working well thus far. One of the application requirements is that the data file must be human-readable plain text, meaning the file can be imported into Excel or opened by Notepad. I'm using a variable length record format much like CSV that I've successfully implemented using the C standard library file I/O functions. When saving a record, I have to calculate whether the updated record is larger or smaller than the version of the record currently in the data file. If larger, I first shift all records immediately after the current record forward by the size difference calculated before saving the updated record. EOF is extended automatically by the OS to accommodate the extra data. If smaller, I shift all records backwards by my calculated offset. This is working well, however I have found no way to modify the EOF marker or file size to ignore the data after the end of the last record. Most of the time records will grow in size because the data collection program will be filling some of the empty fields with data when saving a record. Records will only shrink in size when a correction is made on an existing entry, or on a normal record save if the descriptive data in the record is longer than what the program reads in memory. In the situation of a shrinking record, after the last record in the file I'm left with whatever data was sitting there before the shift. I have been writing an EOF delimiter into the file after a "shrinking record save" to signal where the end of my records are and space-filling the remaining data, but then I no longer have a clean file until a "growing record save" extends the size of the file over the space-filled area. The truncate() function in unistd.h does not work (I'm now thinking this is for *nix flavors only?). One proposed solution I've seen involves creating a second file and writing all the data you wish to save into that file, and then deleting the original. Since I only have 4MB worth of disk space to use, this works if the file size is less than 2MB minus the size of my program executable and configuration files, but would fail otherwise. It is very likely that when this goes into production, users would end up with a file exceeding 2MB in size. I've looked at Ralph Brown's Interrupt List and the interrupt reference in IBM PC Assembly Language and Programming and I can't seem to find anything to update the file size or similar. Is reducing a file's size without creating a second file even possible in DOS?

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  • How and why do I set up a C# build machine?

    - by mmr
    Hi all, I'm working with a small (4 person) development team on a C# project. I've proposed setting up a build machine which will do nightly builds and tests of the project, because I understand that this is a Good Thing. Trouble is, we don't have a whole lot of budget here, so I have to justify the expense to the powers that be. So I want to know: What kind of tools/licenses will I need? Right now, we use Visual Studio and Smart Assembly to build, and Perforce for source control. Will I need something else, or is there an equivalent of a cron job for running automated scripts? What, exactly, will this get me, other than an indication of a broken build? Should I set up test projects in this solution (sln file) that will be run by these scripts, so I can have particular functions tested? We have, at the moment, two such tests, because we haven't had the time (or frankly, the experience) to make good unit tests. What kind of hardware will I need for this? Once a build has been finished and tested, is it a common practice to put that build up on an ftp site or have some other way for internal access? The idea is that this machine makes the build, and we all go to it, but can make debug builds if we have to. How often should we make this kind of build? How is space managed? If we make nightly builds, should we keep around all the old builds, or start to ditch them after about a week or so? Is there anything else I'm not seeing here? I realize that this is a very large topic, and I'm just starting out. I couldn't find a duplicate of this question here, and if there's a book out there I should just get, please let me know. EDIT: I finally got it to work! Hudson is completely fantastic, and FxCop is showing that some features we thought were implemented were actually incomplete. We also had to change the installer type from Old-And-Busted vdproj to New Hotness WiX. Basically, for those who are paying attention, if you can run your build from the command line, then you can put it into hudson. Making the build run from the command line via MSBuild is a useful exercise in itself, because it forces your tools to be current.

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  • Good style for handling constructor failure of critical object

    - by mtlphil
    I'm trying to decide between two ways of instantiating an object & handling any constructor exceptions for an object that is critical to my program, i.e. if construction fails the program can't continue. I have a class SimpleMIDIOut that wraps basic Win32 MIDI functions. It will open a MIDI device in the constructor and close it in the destructor. It will throw an exception inherited from std::exception in the constructor if the MIDI device cannot be opened. Which of the following ways of catching constructor exceptions for this object would be more in line with C++ best practices Method 1 - Stack allocated object, only in scope inside try block #include <iostream> #include "simplemidiout.h" int main() { try { SimpleMIDIOut myOut; //constructor will throw if MIDI device cannot be opened myOut.PlayNote(60,100); //..... //myOut goes out of scope outside this block //so basically the whole program has to be inside //this block. //On the plus side, it's on the stack so //destructor that handles object cleanup //is called automatically, more inline with RAII idiom? } catch(const std::exception& e) { std::cout << e.what() << std::endl; std::cin.ignore(); return 1; } std::cin.ignore(); return 0; } Method 2 - Pointer to object, heap allocated, nicer structured code? #include <iostream> #include "simplemidiout.h" int main() { SimpleMIDIOut *myOut; try { myOut = new SimpleMIDIOut(); } catch(const std::exception& e) { std::cout << e.what() << std::endl; delete myOut; return 1; } myOut->PlayNote(60,100); std::cin.ignore(); delete myOut; return 0; } I like the look of the code in Method 2 better, don't have to jam my whole program into a try block, but Method 1 creates the object on the stack so C++ manages the object's life time, which is more in tune with RAII philosophy isn't it? I'm still a novice at this so any feedback on the above is much appreciated. If there's an even better way to check for/handle constructor failure in a siatuation like this please let me know.

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  • How to drop null values with a native Oracle XML DB Web Service?

    - by gfjr
    I am using native Oracle XML DB Web Services (using a PL/SQL function with a web service). I want to drop null values (put nothing in the output (no XML element)). It's working with Oracle 11.2.0.1.0 but not with Oracle 11.2.0.3.0. Just to clarify... I don't want to consume a webservice with PL/SQL, I want to publish my PL/SQL packages/procedures/functions as a web service! Hope someone can help me. Thank you. In this example is the column "country" null. Oracle 11.2.0.1.0 (this is what I want): <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <GET_PERSONOutput xmlns="http://xmlns.oracle.com/orawsv/TESTSTUFF/GET_PERSON"> <RETURN> <PERSON> <PERSON_ID>3</PERSON_ID> <FIRST_NAME>Harry</FIRST_NAME> <LAST_NAME>Potter</LAST_NAME> </PERSON> </RETURN> </GET_PERSONOutput> </soap:Body> </soap:Envelope> Oracle 11.2.0.3.0: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <GET_PERSONOutput xmlns="http://xmlns.oracle.com/orawsv/TESTSTUFF/GET_PERSON"> <RETURN> <PERSON> <PERSON_ID>3</PERSON_ID> <FIRST_NAME>Harry</FIRST_NAME> <LAST_NAME>Potter</LAST_NAME> <COUNTRY/> </PERSON> </RETURN> </GET_PERSONOutput> </soap:Body> </soap:Envelope>

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  • Overwhelmed by design patterns... where to begin?

    - by Pete
    I am writing a simple prototype code to demonstrate & profile I/O schemes (HDF4, HDF5, HDF5 using parallel IO, NetCDF, etc.) for a physics code. Since focus is on IO, the rest of the program is very simple: class Grid { public: floatArray x,y,z; }; class MyModel { public: MyModel(const int &nip1, const int &njp1, const int &nkp1, const int &numProcs); Grid grid; map<string, floatArray> plasmaVariables; }; Where floatArray is a simple class that lets me define arbitrary dimensioned arrays and do mathematical operations on them (i.e. x+y is point-wise addition). Of course, I could use better encapsulation (write accessors/setters, etc.), but that's not the concept I'm struggling with. For the I/O routines, I am envisioning applying simple inheritance: Abstract I/O class defines read & write functions to fill in the "myModel" object HDF4 derived class HDF5 HDF5 using parallel IO NetCDF etc... The code should read data in any of these formats, then write out to any of these formats. In the past, I would add an AbstractIO member to myModel and create/destroy this object depending on which I/O scheme I want. In this way, I could do something like: myModelObj.ioObj->read('input.hdf') myModelObj.ioObj->write('output.hdf') I have a bit of OOP experience but very little on the Design Patterns front, so I recently acquired the Gang of Four book "Design Patterns: Elements of Reusable Object-Oriented Software". OOP designers: Which pattern(s) would you recommend I use to integrate I/O with the myModel object? I am interested in answering this for two reasons: To learn more about design patterns in general Apply what I learn to help refactor an large old crufty/legacy physics code to be more human-readable & extensible. I am leaning towards applying the Decerator pattern to myModel, so I can attach the I/O responsibilities dynamically to myModel (i.e. whether to use HDF4, HDF5, etc.). However, I don't feel very confident that this is the best pattern to apply. Reading the Gang of Four book cover-to-cover before I start coding feels like a good way to develop an unhealthy caffeine addiction. What patterns do you recommend?

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  • Error Handling for Application in PHP

    - by Zubair1
    I was wondering if someone can show me a good way to handle errors in my PHP app, that i am also easily able to reuse in my codes. So far i have been using the following functions: Inline Errors function display_errors_for($fieldname) { global $errors; if (isset($errors[$fieldname])) { return '<label for="' .$fieldname. '" class="error">' . ucfirst($errors[$fieldname]). '</label>'; } else { return false; } } All Errrors function display_all_errors($showCounter = true) { global $errors; $counter = 0; foreach ($errors as $errorFieldName => $errorText) { if ($showCounter == true) { $counter++; echo '<li>' . $counter . ' - <label for="' .$errorFieldName. '">' .$errorText. '</label></li>'; } else { echo '<li><label for="' .$errorFieldName. '">' .$errorText. '</label></li>'; } } } I have a $errors = array(); defined on the top of my global file, so it is appended to all files. The way i use it is that if i encounter an error, i push a new error key/value to the $errors array holder, something like the following: if (strlen($username) < 3) { $errors['username'] = "usernames cannot be less then 3 characters."; } This all works great and all, But i wondering if some one has a better approach for this? with classes? i don't think i want to use Exceptions with try/catch seems like an overkill to me. I'm planning to make a new app, and i'll be getting my hands wet with OOP alot, though i have already made apps using OOP but this time i'm planning to go even deeper and use OOP approach more extensively. What i have in mind is something like this, though its just a basic class i will add further detail to it as i go deeper and deeper in my app to see what it needs. class Errors { public $errors = array(); public function __construct() { // Initialize Default Values // Initialize Methods } public function __destruct() { //nothing here too... } public function add($errorField, $errorDesc) { if (!is_string($errorField)) return false; if (!is_string($errorDesc)) return false; $this->errors[$errorField] = $errorDesc; } public function display($errorsArray) { // code to iterate through the array and display all errors. } } Please share your thoughts, if this is a good way to make a reusable class to store and display errors for an entire app, or is getting more familiar with exceptions and try/catch my only choice?

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  • What is the most elegant way to implement a business rule relating to a child collection in LINQ?

    - by AaronSieb
    I have two tables in my database: Wiki WikiId ... WikiUser WikiUserId (PK) WikiId UserId IsOwner ... These tables have a one (Wiki) to Many (WikiUser) relationship. How would I implement the following business rule in my LINQ entity classes: "A Wiki must have exactly one owner?" I've tried updating the tables as follows: Wiki WikiId (PK) OwnerId (FK to WikiUser) ... WikiUser WikiUserId (PK) WikiId UserId ... This enforces the constraint, but if I remove the owner's WikiUser record from the Wiki's WikiUser collection, I recieve an ugly SqlException. This seems like it would be difficult to catch and handle in the UI. Is there a way to perform this check before the SqlException is generated? A better way to structure my database? A way to catch and translate the SqlException to something more useful? Edit: I would prefer to keep the validation rules within the LINQ entity classes if possible. Edit 2: Some more details about my specific situation. In my application, the user should be able to remove users from the Wiki. They should be able to remove any user, except the user who is currently flagged as the "owner" of the Wiki (a Wiki must have exactly one owner at all times). In my control logic, I'd like to use something like this: wiki.WikiUsers.Remove(wikiUser); mRepository.Save(); And have any broken rules transferred to the UI layer. What I DON'T want to have to do is this: if(wikiUser.WikiUserId != wiki.OwnerId) { wiki.WikiUsers.Remove(wikiUser); mRepository.Save(); } else { //Handle errors. } I also don't particularly want to move the code to my repository (because there is nothing to indicate not to use the native Remove functions), so I also DON'T want code like this: mRepository.RemoveWikiUser(wiki, wikiUser) mRepository.Save(); This WOULD be acceptable: try { wiki.WikiUsers.Remove(wikiUser); mRepository.Save(); } catch(ValidationException ve) { //Display ve.Message } But this catches too many errors: try { wiki.WikiUsers.Remove(wikiUser); mRepository.Save(); } catch(SqlException se) { //Display se.Message } I would also PREFER NOT to explicitly call a business rule check (although it may become necessary): wiki.WIkiUsers.Remove(wikiUser); if(wiki.CheckRules()) { mRepository.Save(); } else { //Display broken rules }

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  • How do I use a custom #theme function to a fieldset in a drupal module?

    - by Rob Crowell
    I have a module that builds a form that includes a fieldset. Instead of using the <legend> element to render the fieldset title, I want to place this content in a <div> element instead. But I want to change the behavior only for the form returned by my module, so I don't want to place any new functionality into my theme's template.php file. In mymod.module I have defined: // custom rendering function for fieldset elements function theme_mymod_fieldset($element) { return 'test'; } // implement hook_theme function mymod_theme() { return array( 'mymod_fieldset' => array('arguments' => array('element' => NULL)), 'mymod_form' => array('arguments' => array()) ); } // return a form that is based on the 'Basic Account Info' category of the user profile function mymod_form() { // load the user's profile global $user; $account = user_load($user->uid); // load the profile form, and then edit it $form_state = array(); $form = drupal_retrieve_form('user_profile_form', $form_state, $account, 'Basic Account Info'); // set the custom #theme function for this fieldset $form['Basic Account Info']['#theme'] = 'mymod_fieldset'; // more form manipulations // ... return $form; } When my page gets rendered, I expected to see the fieldset representing 'Basic Account Info' to be wholly replaced by my test message 'test'. Instead what happens is that the <fieldset> and <legend> elements are rendered as normal, but with the body of the fieldset replaced by the test message instead, like this: <fieldset> <legend>Basic Account Info</legend> test </fieldset> Why doesn't my #theme function have the chance to replace the entire <fieldset> element? If I wrap a textfield in this function instead, I am able to completely replace the <input> element along with its label. Furthermore, if I provide an override in my site's template.php for theme_fieldset, it works as expected and I am able to completely replace the <fieldset>, so I know it is possible. What's different about providing #theme functions to fieldsets inside a module?

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  • How can I have a Makefile automatically rebuild source files that include a modified header file? (I

    - by Nicholas Flynt
    I have the following makefile that I use to build a program (a kernel, actually) that I'm working on. Its from scratch and I'm learning about the process, so its not perfect, but I think its powerful enough at this point for my level of experience writing makefiles. AS = nasm CC = gcc LD = ld TARGET = core BUILD = build SOURCES = source INCLUDE = include ASM = assembly VPATH = $(SOURCES) CFLAGS = -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions \ -nostdinc -fno-builtin -I $(INCLUDE) ASFLAGS = -f elf #CFILES = core.c consoleio.c system.c CFILES = $(foreach dir,$(SOURCES),$(notdir $(wildcard $(dir)/*.c))) SFILES = assembly/start.asm SOBJS = $(SFILES:.asm=.o) COBJS = $(CFILES:.c=.o) OBJS = $(SOBJS) $(COBJS) build : $(TARGET).img $(TARGET).img : $(TARGET).elf c:/python26/python.exe concat.py stage1 stage2 pad.bin core.elf floppy.img $(TARGET).elf : $(OBJS) $(LD) -T link.ld -o $@ $^ $(SOBJS) : $(SFILES) $(AS) $(ASFLAGS) $< -o $@ %.o: %.c @echo Compiling $<... $(CC) $(CFLAGS) -c -o $@ $< #Clean Script - Should clear out all .o files everywhere and all that. clean: -del *.img -del *.o -del assembly\*.o -del core.elf My main issue with this makefile is that when I modify a header file that one or more C files include, the C files aren't rebuilt. I can fix this quite easily by having all of my header files be dependencies for all of my C files, but that would effectively cause a complete rebuild of the project any time I changed/added a header file, which would not be very graceful. What I want is for only the C files that include the header file I change to be rebuilt, and for the entire project to be linked again. I can do the linking by causing all header files to be dependencies of the target, but I cannot figure out how to make the C files be invalidated when their included header files are newer. I've heard that GCC has some commands to make this possible (so the makefile can somehow figure out which files need to be rebuilt) but I can't for the life of me find an actual implementation example to look at. Can someone post a solution that will enable this behavior in a makefile? EDIT: I should clarify, I'm familiar with the concept of putting the individual targets in and having each target.o require the header files. That requires me to be editing the makefile every time I include a header file somewhere, which is a bit of a pain. I'm looking for a solution that can derive the header file dependencies on its own, which I'm fairly certain I've seen in other projects.

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  • WPF/C#: How to simplify the use of codes when calling a function (Generating Images)

    - by eibhrum
    I created a function in one of my application that allows to generate an image (in WPF) by getting the 'source path' from the database that I am using: public void ShowImageThumb() { try { cn = new MySqlConnection(); cn.ConnectionString = ConfigurationManager.AppSettings["MyConnection"]; cn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd.Connection = cn; cmd.CommandType = CommandType.Text; cmd.CommandText = "SELECT thumb FROM album WHERE thumbNo=1"; MySqlDataAdapter adp = new MySqlDataAdapter(); adp.SelectCommand = cmd; DataTable dt = new DataTable(); adp.Fill(dt); MySqlDataReader r = cmd.ExecuteReader(); while (r.Read()) { BitmapImage bmi1 = new BitmapImage(new Uri(r[0].ToString(), UriKind.Relative)); image1.Source = bmi1; } r.Close(); cn.Close(); } catch (Exception err){ System.Windows.MessageBox.Show(err.Message); } finally { } } Take a look on my SQL statement. I put a WHERE thumbNo=1 which allows the function to get 1 record. You see, I do have at least 10 records - file paths listed in that table. I just wanna ask if there's a possible way to make my SQL statement something like this: SELECT thumb FROM album; while having this piece of code inserted in my function: BitmapImage bmi2 = new BitmapImage(new Uri(r["second record?"].ToString(), UriKind.Relative)); image2.Source = bmi2; //something like this BitmapImage bmi3 = new BitmapImage(new Uri(r["third record?"].ToString(), UriKind.Relative)); image3.Source = bmi3; //something like this and so on and so forth, without ending up creating 10 different functions for 10 records. ShowImageThumb2(); . . // will not do this . ShowImageThumb10(); Sorry for the lengthy post. I hope somebody could answer back. Thanks!

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  • Passing Variables Along in a Function

    - by John
    Hello, In the function show_commentbox() below, I would like to pass along the variables $_SESSION['loginid'], $submissionid, $submission, $url, $submittor, $submissiondate, $countcomments, $dispurl. With the setup below, it's not working. How could I change it to make show_commentbox() pass the variables along? Thanks in advance, John index.php: <?php $submission = $_GET['submission']; require_once "header.php"; include "login.php"; include "comments.php"; include "commentformonoff.php"; ?> In header.php: require_once ("function.inc.php"); In comments.php: $uid = $_SESSION['loginid']; $submissiondate = mysql_real_escape_string($_GET['submissiondate']); $submittor = mysql_real_escape_string($_GET['submittor']); $countcomments = mysql_real_escape_string($_GET['countcomments']); $dispurl = mysql_real_escape_string($_GET['dispurl']); $url = mysql_real_escape_string($_GET['url']); $submission = mysql_real_escape_string($_GET['submission']); $submissionid = mysql_real_escape_string($_GET['submissionid']); commentformonoff.php: <?php if (!isLoggedIn()) { if (isset($_POST['cmdlogin'])) { if (checkLogin($_POST['username'], $_POST['password'])) { show_commentbox(); } else { echo "Login to comment"; } } else { echo "Login to comment"; } } else { show_commentbox(); } ?> In display.functions.inc.php: function show_commentbox() { echo '<form action="http://www...com/sandbox/comments/comments2.php" method="post"> <input type="hidden" value="'.$_SESSION['loginid'].'" name="uid"> <input type="hidden" value="'.$submissionid.'" name="submissionid"> <input type="hidden" value="'.$submission.'" name="submission"> <input type="hidden" value="'.$url.'" name="url"> <input type="hidden" value="'.$submittor.'" name="submittor"> <input type="hidden" value="'.$submissiondate.'" name="submissiondate"> <input type="hidden" value="'.$countcomments.'" name="countcomments"> <input type="hidden" value="'.$dispurl.'" name="dispurl"> <label class="addacomment" for="title">Add a comment:</label> <textarea class="commentsubfield" name="comment" type="comment" id="comment" maxlength="1000"></textarea> <div class="commentsubbutton"><input name="submit" type="submit" value="Submit"></div> </form> '; }

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  • PHP 'instanceof' failing with class constant

    - by Nathan Loding
    I'm working on a framework that I'm trying to type as strongly as I possibly can. (I'm working within PHP and taking some of the ideas that I like from C# and trying to utilize them within this framework.) I'm creating a Collection class that is a collection of domain entities/objects. It's kinda modeled after the List<T> object in .Net. I've run into an obstacle that is preventing me from typing this class. If I have a UserCollection, it should only allow User objects into it. If I have a PostCollection, it should only allow Post objects. All Collections in this framework need to have certain basic functions, such as add, remove, iterate. I created an interface, but found that I couldn't do the following: interface ICollection { public function add($obj) } class PostCollection implements ICollection { public function add(Post $obj) {} } This broke it's compliance with the interface. But I can't have the interface strongly typed because then all Collections are of the same type. So I attempted the following: interface ICollection { public function add($obj) } abstract class Collection implements ICollection { const type = 'null'; } class PostCollection { const type = 'Post'; public function add($obj) { if(!($obj instanceof self::type)) { throw new UhOhException(); } } } When I attempt to run this code, I get syntax error, unexpected T_STRING, expecting T_VARIABLE or '$' on the instanceof statement. A little research into the issue and it looks like the root of the cause is that $obj instanceof self is valid to test against the class. It appears that PHP doesn't process the entire self::type constant statement in the expression. Adding parentheses around the self::type variable threw an error regarding an unexpected '('. An obvious workaround is to not make the type variable a constant. The expression $obj instanceof $this->type works just fine (if $type is declared as a variable, of course). I'm hoping that there's a way to avoid that, as I'd like to define the value as a constant to avoid any possible change in the variable later. Any thoughts on how I can achieve this, or have I take PHP to it's limit in this regard? Is there a way of "escaping" or encapsulating self::this so that PHP won't die when processing it?

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  • Using pointers, references, handles to generic datatypes, as generic and flexible as possible

    - by Patrick
    In my application I have lots of different data types, e.g. Car, Bicycle, Person, ... (they're actually other data types, but this is just for the example). Since I also have quite some 'generic' code in my application, and the application was originally written in C, pointers to Car, Bicycle, Person, ... are often passed as void-pointers to these generic modules, together with an identification of the type, like this: Car myCar; ShowNiceDialog ((void *)&myCar, DATATYPE_CAR); The 'ShowNiceDialog' method now uses meta-information (functions that map DATATYPE_CAR to interfaces to get the actual data out of Car) to get information of the car, based on the given data type. That way, the generic logic only has to be written once, and not every time again for every new data type. Of course, in C++ you could make this much easier by using a common root class, like this class RootClass { public: string getName() const = 0; }; class Car : public RootClass { ... }; void ShowNiceDialog (RootClass *root); The problem is that in some cases, we don't want to store the data type in a class, but in a totally different format to save memory. In some cases we have hundreds of millions of instances that we need to manage in the application, and we don't want to make a full class for every instance. Suppose we have a data type with 2 characteristics: A quantity (double, 8 bytes) A boolean (1 byte) Although we only need 9 bytes to store this information, putting it in a class means that we need at least 16 bytes (because of the padding), and with the v-pointer we possibly even need 24 bytes. For hundreds of millions of instances, every byte counts (I have a 64-bit variant of the application and in some cases it needs 6 GB of memory). The void-pointer approach has the advantage that we can almost encode anything in a void-pointer and decide how to use it if we want information from it (use it as a real pointer, as an index, ...), but at the cost of type-safety. Templated solutions don't help since the generic logic forms quite a big part of the application, and we don't want to templatize all this. Additionally, the data model can be extended at run time, which also means that templates won't help. Are there better (and type-safer) ways to handle this than a void-pointer? Any references to frameworks, whitepapers, research material regarding this?

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  • How to define an extern, C struct returning function in C++ using MSVC?

    - by DK
    The following source file will not compile with the MSVC compiler (v15.00.30729.01): /* stest.c */ #ifdef __cplusplus extern "C" { #endif struct Test; extern struct Test make_Test(int x); struct Test { int x; }; extern struct Test make_Test(int x) { struct Test r; r.x = x; return r; } #ifdef __cplusplus } #endif Compiling with cl /c /Tpstest.c produces the following error: stest.c(8) : error C2526: 'make_Test' : C linkage function cannot return C++ class 'Test' stest.c(6) : see declaration of 'Test' Compiling without /Tp (which tells cl to treat the file as C++) works fine. The file also compiles fine in DigitalMars C and GCC (from mingw) in both C and C++ modes. I also used -ansi -pedantic -Wall with GCC and it had no complaints. For reasons I will go into below, we need to compile this file as C++ for MSVC (not for the others), but with functions being compiled as C. In essence, we want a normal C compiler... except for about six lines. Is there a switch or attribute or something I can add that will allow this to work? The code in question (though not the above; that's just a reduced example) is being produced by a code generator. As part of this, we need to be able to generate floating point nans and infinities as constants (long story), meaning we have to compile with MSVC in C++ mode in order to actually do this. We only found one solution that works, and it only works in C++ mode. We're wrapping the code in extern "C" {...} because we want to control the mangling and calling convention so that we can interface with existing C code. ... also because I trust C++ compilers about as far as I could throw a smallish department store. I also tried wrapping just the reinterpret_cast line in extern "C++" {...}, but of course that doesn't work. Pity. There is a potential solution I found which requires reordering the declarations such that the full struct definition comes before the function foward decl., but this is very inconvenient due to the way the codegen is performed, so I'd really like to avoid having to go down that road if I can.

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  • C program using inotify to monitor multiple directories along with sub-directories?

    - by lakshmipathi
    I have program which monitors a directory (/test) and notify me. I want to improve this to monitor another directory (say /opt). And also how to monitor it's subdirectories , current i'll get notified if any changes made to files under /test . but i'm not getting any inotifcation if changes made sub-directory of /test, that is touch /test/sub-dir/files.txt .. Here my current code - hope this will help /* Simple example for inotify in Linux. inotify has 3 main functions. inotify_init1 to initialize inotify_add_watch to add monitor then inotify_??_watch to rm monitor.you the what to replace with ??. yes third one is inotify_rm_watch() */ #include <sys/inotify.h> int main(){ int fd,wd,wd1,i=0,len=0; char pathname[100],buf[1024]; struct inotify_event *event; fd=inotify_init1(IN_NONBLOCK); /* watch /test directory for any activity and report it back to me */ wd=inotify_add_watch(fd,"/test",IN_ALL_EVENTS); while(1){ //read 1024 bytes of events from fd into buf i=0; len=read(fd,buf,1024); while(i<len){ event=(struct inotify_event *) &buf[i]; /* check for changes */ if(event->mask & IN_OPEN) printf("%s :was opened\n",event->name); if(event->mask & IN_MODIFY) printf("%s : modified\n",event->name); if(event->mask & IN_ATTRIB) printf("%s :meta data changed\n",event->name); if(event->mask & IN_ACCESS) printf("%s :was read\n",event->name); if(event->mask & IN_CLOSE_WRITE) printf("%s :file opened for writing was closed\n",event->name); if(event->mask & IN_CLOSE_NOWRITE) printf("%s :file opened not for writing was closed\n",event->name); if(event->mask & IN_DELETE_SELF) printf("%s :deleted\n",event->name); if(event->mask & IN_DELETE) printf("%s :deleted\n",event->name); /* update index to start of next event */ i+=sizeof(struct inotify_event)+event->len; } } }

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