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  • Querying using table-valued parameter

    - by antmx
    I need help please with writing a sproc, it takes a table-valued parameter @Locations, whose Type is defined as follows: CREATE TYPE [dbo].[tvpLocation] AS TABLE( [CountryId] [int] NULL, [ResortName] [nvarchar](100) NULL, [Ordinal] [int] NOT NULL, PRIMARY KEY CLUSTERED ( [Ordinal] ASC )WITH (IGNORE_DUP_KEY = OFF) ) @Locations will contain at least 1 row. Each row WILL have a non-null CountryId, and MAY have a non-null ResortName. Each row will have a unique Ordinal, the first being 0. The combinations of CountryId and ResortName in @Locations will be unique. The sproc needs to search against the following table structure. The image can be seen better by right-clicking it and View Image, or similar depending on your browser. Now this is where I'm stuck, the sproc should be able to find Tours where: The Tour's 1st TourHotel (Ordinal 0) has the same CountryId (and ResortName if specified) of the 1st row of @Locations (Ordinal 0). And also if @Locations has 1 row, the Tour must have additional TourHotels, ALL of which must be in the remaining CountryIds (and ResortNames if specified) of these remaining @Locations rows. Edit This is the code I finally used, based on Anthony Faull's suggestion. Thank you so much Anthony: select distinct T.Id from tblTour T join tblTourHotel TH on TH.TourId = T.Id join tblHotel H ON H.Id = TH.HotelId JOIN @Locations L ON ( ( L.Ordinal = 0 AND TH.Ordinal = 0 ) OR ( L.Ordinal > 0 AND TH.Ordinal > 0 ) ) AND L.CountryId = H.CountryId AND ( L.ResortName = H.ResortName OR L.ResortName IS NULL ) cross apply( select COUNT(TH2.Id) AS [Count] FROM tblTourHotel TH2 where TH2.TourId = TH.TourId ) TourHotelCount where TourHotelCount.[Count] = @LocationCount group by T.Id, T.TourRef, T.Description, T.DepartureDate, T.NumNights, T.DepartureAirportId, T.DestinationAirportId, T.AirlineId, T.FEPrice having COUNT(distinct TH.Id) = @LocationCount

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  • Why isn't this json/jquery function returning 10 results and why does it return 0 sometimes?

    - by Scarface
    Hey guys, quick question. I have a json function returning results from a php query but it is not working out because it seems to keep executing the query until all results are returned and sometimes returns 0 results (if I keep refreshing page, it returns 0 results sometimes). I want to limit results returned to 10 so I was wondering if anyone could point out the error of my code. Would really appreciate it. PS I am positive the query is returning the correct results and only 10 on its own. It just seems to be this one function that is not working out. SELECT time, user, comment FROM comments WHERE topic_id='$topic_id' ORDER BY time DESC LIMIT 10 var count=0; function prepare(response) { count++; var string = '<li class="list" id="list-'+count+'">' +'</li>'; return string; } $.getJSON(files+"comments.php?action=view&load=initial&topic_id="+topic_id+"&t=" + (new Date()), function(json) { if(json.length) { for(i=0; i < json.length; i++) { $('#shoutbox-list').prepend(prepare(json[i])); $('#list-' + count).fadeIn(1500); } var j = i-1; lastTime = json[j].time; } });

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  • Overhead of calling tiny functions from a tight inner loop? [C++]

    - by John
    Say you see a loop like this one: for(int i=0; i<thing.getParent().getObjectModel().getElements(SOME_TYPE).count(); ++i) { thing.getData().insert( thing.GetData().Count(), thing.getParent().getObjectModel().getElements(SOME_TYPE)[i].getName() ); } if this was Java I'd probably not think twice. But in performance-critical sections of C++, it makes me want to tinker with it... however I don't know if the compiler is smart enough to make it futile. This is a made up example but all it's doing is inserting strings into a container. Please don't assume any of these are STL types, think in general terms about the following: Is having a messy condition in the for loop going to get evaluated each time, or only once? If those get methods are simply returning references to member variables on the objects, will they be inlined away? Would you expect custom [] operators to get optimized at all? In other words is it worth the time (in performance only, not readability) to convert it to something like: ElementContainer &source = thing.getParent().getObjectModel().getElements(SOME_TYPE); int num = source.count(); Store &destination = thing.getData(); for(int i=0;i<num;++i) { destination.insert(thing.GetData().Count(), source[i].getName(); } Remember, this is a tight loop, called millions of times a second. What I wonder is if all this will shave a couple of cycles per loop or something more substantial? Yes I know the quote about "premature optimisation". And I know that profiling is important. But this is a more general question about modern compilers, Visual Studio in particular.

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  • Getting the current item number or index when using will_paginate in rails app

    - by Rich
    I have a rails app that stores movies watched, books read, etc. The index page for each type lists paged collections of all its items, using will_paginate to bring back 50 items per page. When I output the items I want to display a number to indicate what item in the total collection it is. The numbering should be reversed as the collection is displayed with most recent first. This might not relate to will_paginate but rather some other method of calculation. I will be using the same ordering in multiple types so it will need to be reusable. As an example, say I have 51 movies. The first item of the first page should display: Fight Club - Watched: 30th Dec 2010 Whilst the last item on the page should display: The Matrix - Watched: 3rd Jan 2010 The paged collection is available as an instance variable e.g. @movies, and @movies.count will display the number of items in the paged collection. So if we're on page 1, movies.count == 50, whilst on page 2 @movies.count == 1. Using Movie.count would give 51. If the page number and page size can be accessed the number could be calculated so how can they be returned? Though I'm hopeful there is something that already exists to handle this calculation!

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  • Unexpected crash while using looking phone numbers in iPhone address book

    - by FX
    I have a rather unexpected result with the following code: ABAddressBookRef addressBook = ABAddressBookCreate(); CFArrayRef people = ABAddressBookCopyArrayOfAllPeople(addressBook); CFIndex nPeople = ABAddressBookGetPersonCount(addressBook); NSLog (@"npeople = %d = %d", nPeople, CFArrayGetCount(people)); for (CFIndex i = 0; i < nPeople; i++) { ABRecordRef record = CFArrayGetValueAtIndex(people,i); ABMultiValueRef numbers = ABRecordCopyValue(record, kABPersonPhoneProperty); CFIndex count = ABMultiValueGetCount(numbers); NSLog (@"%d %d", i, count); } I never reach the second NSLog, it crashes on the call to ABMultiValueGetCount with: : * -[NSCFString count]: unrecognized selector sent to instance 0x383e72f4 : Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '** -[NSCFString count]: unrecognized selector sent to instance 0x383e72f4' In short, it's behaving as if my "numbers" variable was an NSString. While I wrote the code above myself, the same can be found in many examples on the web. Does someone here spot anything wrong with it? Oh, and also: it only crashes in Release mode (in debug mode, all is fine).

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  • Passing Data to Multi Threads

    - by alaamh
    I study this code from some book: #include <pthread.h> #include <stdio.h> /* Parameters to print_function. */ struct char_print_parms { /* The character to print. */ char character; /* The number of times to print it. */ int count; }; /* Prints a number of characters to stderr, as given by PARAMETERS, which is a pointer to a struct char_print_parms. */ void* char_print(void* parameters) { /* Cast the cookie pointer to the right type. */ struct char_print_parms* p = (struct char_print_parms*) parameters; int i; for (i = 0; i < p->count; ++i) fputc(p->character, stderr); return NULL; } /* The main program. */ int main() { pthread_t thread1_id; pthread_t thread2_id; struct char_print_parms thread1_args; struct char_print_parms thread2_args; /* Create a new thread to print 30,000 ’x’s. */ thread1_args.character = 'x'; thread1_args.count = 30000; pthread_create(&thread1_id, NULL, &char_print, &thread1_args); /* Create a new thread to print 20,000 o’s. */ thread2_args.character = 'o'; thread2_args.count = 20000; pthread_create(&thread2_id, NULL, &char_print, &thread2_args); usleep(20); return 0; } after running this code, I see different result each time. and some time corrupted result. what is wrong and what the correct way to do that?

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  • Retrieving Relationships from within two arrays of pointers

    - by DanF
    In a portion of a program I'm working on, I need to count all the times each person has worked on projects with each other person. Let's say we have "Employee" entities and "Session" entities. In each session, there are four project types, "A", "B", "C", & "D", each a many-to-many relationship to Employees. I'm making a loop to systematically review every person a selected person has worked with. First, I put all their project types in a single array, so it's easier to loop through, but by the time I ask the last nested Project for its Employee members, I get an "unrecognized selector" error. IBOutlet NSArrayController * list; int x; for(x = 0; x < [list count]; x++){ NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectAs"]; NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectBs"]; NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectCs"]; NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectDs"]; NSArray *masterList = [[NSArray alloc] initWithObjects: projectAs, projectBs, projectCs, projectDs, nil]; int y; for(y = 0; y < [masterList count]; y++){ int z; for(z = 0; z < [[masterlist objectAtIndex:y] count]; z++){ //And now to make an Array of this employee's partners on the selected object, to run comparisons on. //I also have an array of keys for each session's teams, so that's what I'm referencing here: NSArray * thisTeam = [list objectAtIndex:y] objectAtIndex:z] valueForKey:projectKey]; This throws an exception... namely, -[_NSFaultingMutableSet objectAtIndex:]: unrecognized selector sent to instance What's wrong with that last Array creation?

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  • How i can fix the increasing order summation code?

    - by user2971559
    I want from the java to reads all numbers from the user as long as the number entered by user is bigger than the previous number. But i could write it for only positive numbers. How i can fix code below if all numbers included. If it is possible please write the solution for beginners because its my first year in computer science in college and I haven't learn a lot yet. import acm.program.*; public class IncreasingOrder extends ConsoleProgram { public void run() { int previousNumber = 0; int total = 0; int count = 0; while(true) { int n = readInt("Enter > "); if (n <= previousNumber) break; total += n; count++; previousNumber = n; } println("You have entered " + count + " numbers in increasing order."); println("Sum of these " + count + " numbers is " + total + "."); } }

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  • Finding the Largest and Smallest Integers In A Set- Basic

    - by Ka112324
    I'm kind of on the right track, however my output is not quite right. The program asks for the number of integers you have and then it asks for those numbers. For an example is says please enter the number of integers, you can put 3. And then you enter 3 numbers. I can't use arrays because I am a beginner student and we have not learned those yet. Using count is the only way that allows me to input integers. What do I need to add to my program? Again I am a general computer science student so I can't use anything advanced. I used include iostream, namespace int main and all that you just cant see it int data; int num; int count=0; int max=0; do { cout<<"Enter the number of intergers"<<endl; cin>>num; while (count<num) { cout<<"Please enter a number"<<endl; cin>>data; count++; if (data<min) { min=data; } if (data>max) { max=data; } } cout<<"Smallest integer:"<<min<<endl; cout<<"Largest integer:"<<max<<endl; cout<<"Would you like to continue?"<<endl; cin>>ans; } while ((ans=='y')||(ans=='Y')); return 0; }

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  • LinQ optimization

    - by Budda
    Here is a peace of code: void MyFunc(List<MyObj> objects) { MyFunc1(objects); foreach( MyObj obj in objects.Where(obj1=>obj1.Good)) { // Do Action With Good Object } } void MyFunc1(List<MyObj> objects) { int iGoodCount = objects.Where(obj1=>obj1.Good).Count(); BeHappy(iGoodCount); // do other stuff with 'objects' collection } Here we see that collection is analyzed twice and each time the value of 'Good' property is checked for each member: 1st time when calculating count of good objects, 2nd - when iterating through all good objects. It is desirable to have that optimized, and here is a straightforward solution: before call to MyFunc1 makecreate an additional temporary collection of good objects only (goodObjects, it can be IEnumerable); get count of these objects and pass it as an additional parameter to MyFunc1; in the 'MyFunc' method iterate not through 'objects.Where(...)' but through the 'goodObjects' collection. Not too bad approach (as far as I see), but additional parameter is required to be passed. Question: is there any LinQ out-of-the-box functionality that allows any caching during 1st Where().Count(), remembering a processed collection and use it in the next iteration? Any thoughts are welcome. Thanks.

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  • Java iterative vs recursive

    - by user1389813
    Can anyone explain why the following recursive method is faster than the iterative one (Both are doing it string concatenation) ? Isn't the iterative approach suppose to beat up the recursive one ? plus each recursive call adds a new layer on top of the stack which can be very space inefficient. private static void string_concat(StringBuilder sb, int count){ if(count >= 9999) return; string_concat(sb.append(count), count+1); } public static void main(String [] arg){ long s = System.currentTimeMillis(); StringBuilder sb = new StringBuilder(); for(int i = 0; i < 9999; i++){ sb.append(i); } System.out.println(System.currentTimeMillis()-s); s = System.currentTimeMillis(); string_concat(new StringBuilder(),0); System.out.println(System.currentTimeMillis()-s); } I ran the program multiple time, and the recursive one always ends up 3-4 times faster than the iterative one. What could be the main reason there that is causing the iterative one slower ?

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  • How to sort NSMutableArray? Code review needed

    - by JAM
    Good evening. This code works. It sorts an array of cards by both Suit and Card Value. It is also very much brute force. Can you recommend a better way? Does Objective-C help dealing with a situation where object being sorted itself has multiple fields, on which sorting depends? -(void) sort: (NSMutableArray *) deck { NSUInteger count = [deck count]; Card *thisCard; Card *nextCard; int this; int next; BOOL stillSwapping = true; while (stillSwapping) { stillSwapping = false; for (NSUInteger i = 0; i < count; ++i) { this = i; next = i+1; if (next < count) { thisCard = [deck objectAtIndex:this]; nextCard = [deck objectAtIndex:next]; if ([thisCard suit] > [nextCard suit]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } if ([thisCard suit] == [nextCard suit]) { if ([thisCard value] > [nextCard value]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } } } } } }

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  • Given a vector of maximum 10 000 natural and distinct numbers, find 4 numbers(a, b, c, d) such that

    - by king_kong
    Hi, I solved this problem by following a straightforward but not optimal algorithm. I sorted the vector in descending order and after that substracted numbers from max to min to see if I get a + b + c = d. Notice that I haven't used anywhere the fact that elements are natural, distinct and 10 000 at most. I suppose these details are the key. Does anyone here have a hint over an optimal way of solving this? Thank you in advance! Later Edit: My idea goes like this: '<<quicksort in descending order>>' for i:=0 to count { // after sorting, loop through the array int d := v[i]; for j:=i+1 to count { int dif1 := d - v[j]; int a := v[j]; for k:=j+1 to count { if (v[k] > dif1) continue; int dif2 := dif1 - v[k]; b := v[k]; for l:=k+1 to count { if (dif2 = v[l]) { c := dif2; return {a, b, c, d} } } } } } What do you think?(sorry for the bad indentation)

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  • How do I grab hold of a pop-up that is opened from a frame?

    - by KLA
    I am testing a website using WatiN. On one of the pages I get a "report" in an Iframe, within this I frame there is a link to download and save the report. But since the only way to get to the link is to use frame.Link(...) the pop-up closes immediately after opening; Code snippet below //Click the create graph button ie.Button(Find.ById("ctl00_ctl00_ContentPlaceHolder1_TopBoxContentPlaceHolder_btnCreateGraph")).Click(); //Lets export the data ie.Div(Find.ById("colorbox")); ie.Div(Find.ById("cboxContent")); ie.Div(Find.ById("cboxLoadedContent")); Thread.Sleep(1000);//Used to cover performance issues Frame frame = ie.Frame(Find.ByName(frameNameRegex)); for (int Count = 0; Count < 10000000; Count++) {double nothing = (Count/12); }//Do nothing I just need a short pause //SelectList waits for a postback which does not occur. try { frame.SelectList(Find.ById("rvReport_ctl01_ctl05_ctl00")).SelectByValue("Excel"); } catch (Exception) { //Do nothing } //Now click export frame.Link(Find.ById("rvReport_ctl01_ctl05_ctl01")).ClickNoWait(); IE ieNewBrowserWindow = IE.AttachTo<IE>(Find.ByUrl(urlRegex)); fileDownloadHandler.WaitUntilFileDownloadDialogIsHandled(150); fileDownloadHandler.WaitUntilDownloadCompleted(200); I have tried using ie instead of frame which is why all those ie.Div's are present. if I use frame the pop-up window opens and closes instantly. If I use ie I get a link not found error. If I click on the link manually, while the test is "trying to find the link" the file will download correctly.

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  • Problems while trying to make a query with variables in the conditions (stored procedure)

    - by pablo89
    Hi!! Im having a problem, Im trying to do a query... I remember that in the past I did something like this but today this query is returning nothing, no error, no data, just nothing... the query is something like this: SELECT field1, @variableX:=field2 FROM table WHERE (SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=0)0 AND (SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=4)=0; I also tried this query but it didnt work (also it gaves no error): SELECT field1, @variableX:=field2, @variableY:=(SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=0), @variableZ:=(SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=4) FROM table WHERE @variableY0 AND @variableZ=0; As you can see, what Im trying to do in the 1st query is use a variable in the conditions; in the 2nd query Im trying to create some variables and evaluate them in the conditions. At the end in the 2nd query the @variableY=1 AND @variableZ=0 but I dont know what the query returns an empty data What could be wrong here??? Any comment or suggest is welcome!!! thanks!!! Bye!!!

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  • Compression Program in C

    - by Delandilon
    I want to compress a series of characters. For example if i type Input : FFFFFBBBBBBBCCBBBAABBGGGGGSSS (27 x 8 bits = 216 bits) Output: F5B7C2B3A2B2G5S3 (14 x 8 bits = 112bits) So far this is what i have, i can count the number of Characters in the Array. But the most important task is to count them in the same sequence. I can't seem to figure that out :( Ive stared doing C just a few weeks back, i have knowledge on Array, pointers, ASCII value but in any case can't seem to count these characters in a sequence. Ive try a bit of everything. This approach is no good but it the closest i came to it. #include <stdio.h> #include <conio.h> int main() { int charcnt=0,dotcnt=0,commacnt=0,blankcnt=0,i, countA, countB; char str[125]; printf("*****String Manipulations*****\n\n"); printf("Enter a string\n\n"); scanf("%[^'\n']s",str); printf("\n\nEntered String is \" %s \" \n",str); for(i=0;str[i]!='\0';i++) { // COUNTING EXCEPTION CHARS if(str[i]==' ') blankcnt++; if(str[i]=='.') dotcnt++; if(str[i]==',') commacnt++; if (str[i]=='A' || str[i]=='a') countA++; if (str[i]=='B' || str[i]=='b') countA++; } //PRINT RESULT OF COUNT charcnt=i; printf("\n\nTotal Characters : %d",charcnt); printf("\nTotal Blanks : %d",blankcnt); printf("\nTotal Full stops : %d",dotcnt); printf("\nTotal Commas : %d\n\n",commacnt); printf("A%d\n", countA); }

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  • Disable a control inside a gridview

    - by saeed talaee
    Hi i want to disable link-bottoms control in a grid view with the condition of a special value . for example if the count for a row become 0 ,the link bottom for that row should be invisible . what should i do? where should i write the code? here is cod that i write in row command grid view but it works only of i push the link bottom!! but i want to apply this cod to my page before loading. please guide me int idx = Convert.ToInt32(e.CommandArgument); idx = idx - (GridView1.PageSize * GridView1.PageIndex); int ID = (int)GridView1.DataKeys[idx].Value; string connStr = ConfigurationManager.ConnectionStrings["dbconn"].ConnectionString; SqlConnection sqlconn = new SqlConnection(connStr); SqlCommand sqlcmd = new SqlCommand(); sqlcmd = new SqlCommand("SELECT count(ID) FROM ReviwerArticle where ArticleID=@ArticleID", sqlconn); sqlcmd.Parameters.AddWithValue("@ArticleID", ID); sqlconn.Open(); int count = ((int)sqlcmd.ExecuteScalar()); sqlconn.Close(); if (count == 0) { ((LinkButton)GridView1.Rows[idx].Cells[0].FindControl("LinkButton4") as LinkButton).Visible = false; }

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  • replacing space with %20

    - by Codenotguru
    The following program replaces all spaces with %20.the compilation works fine but the program terminates during the runtime.Any help??? #include<iostream> #include<string> using namespace std; void removeSpaces(string url){ int len=url.length(); int i,count=0; while(i<=len){ if(url[i]==' ') count++; i++; } int length2=len+(count*2); string newarr[length2]; for(int j=len-1;j>=0;j--){ if(url[j]==' ') { newarr[length2-1]='0'; newarr[length2-2]='2'; newarr[length2-3]='%'; length2=length2-3; } else { newarr[length2-1]=url[j]; length2=length2-1; } } cout<<"\nThe number of spaces in the url is:"<<count; cout<<"\nThe replaced url is:"<<newarr; } int main(){ string url="http://www.ya h o o.com/"; removeSpaces(url); }

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  • Fun with Aggregates

    - by Paul White
    There are interesting things to be learned from even the simplest queries.  For example, imagine you are given the task of writing a query to list AdventureWorks product names where the product has at least one entry in the transaction history table, but fewer than ten. One possible query to meet that specification is: SELECT p.Name FROM Production.Product AS p JOIN Production.TransactionHistory AS th ON p.ProductID = th.ProductID GROUP BY p.ProductID, p.Name HAVING COUNT_BIG(*) < 10; That query correctly returns 23 rows (execution plan and data sample shown below): The execution plan looks a bit different from the written form of the query: the base tables are accessed in reverse order, and the aggregation is performed before the join.  The general idea is to read all rows from the history table, compute the count of rows grouped by ProductID, merge join the results to the Product table on ProductID, and finally filter to only return rows where the count is less than ten. This ‘fully-optimized’ plan has an estimated cost of around 0.33 units.  The reason for the quote marks there is that this plan is not quite as optimal as it could be – surely it would make sense to push the Filter down past the join too?  To answer that, let’s look at some other ways to formulate this query.  This being SQL, there are any number of ways to write logically-equivalent query specifications, so we’ll just look at a couple of interesting ones.  The first query is an attempt to reverse-engineer T-SQL from the optimized query plan shown above.  It joins the result of pre-aggregating the history table to the Product table before filtering: SELECT p.Name FROM ( SELECT th.ProductID, cnt = COUNT_BIG(*) FROM Production.TransactionHistory AS th GROUP BY th.ProductID ) AS q1 JOIN Production.Product AS p ON p.ProductID = q1.ProductID WHERE q1.cnt < 10; Perhaps a little surprisingly, we get a slightly different execution plan: The results are the same (23 rows) but this time the Filter is pushed below the join!  The optimizer chooses nested loops for the join, because the cardinality estimate for rows passing the Filter is a bit low (estimate 1 versus 23 actual), though you can force a merge join with a hint and the Filter still appears below the join.  In yet another variation, the < 10 predicate can be ‘manually pushed’ by specifying it in a HAVING clause in the “q1” sub-query instead of in the WHERE clause as written above. The reason this predicate can be pushed past the join in this query form, but not in the original formulation is simply an optimizer limitation – it does make efforts (primarily during the simplification phase) to encourage logically-equivalent query specifications to produce the same execution plan, but the implementation is not completely comprehensive. Moving on to a second example, the following query specification results from phrasing the requirement as “list the products where there exists fewer than ten correlated rows in the history table”: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) < 10 ); Unfortunately, this query produces an incorrect result (86 rows): The problem is that it lists products with no history rows, though the reasons are interesting.  The COUNT_BIG(*) in the EXISTS clause is a scalar aggregate (meaning there is no GROUP BY clause) and scalar aggregates always produce a value, even when the input is an empty set.  In the case of the COUNT aggregate, the result of aggregating the empty set is zero (the other standard aggregates produce a NULL).  To make the point really clear, let’s look at product 709, which happens to be one for which no history rows exist: -- Scalar aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709;   -- Vector aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709 GROUP BY th.ProductID; The estimated execution plans for these two statements are almost identical: You might expect the Stream Aggregate to have a Group By for the second statement, but this is not the case.  The query includes an equality comparison to a constant value (709), so all qualified rows are guaranteed to have the same value for ProductID and the Group By is optimized away. In fact there are some minor differences between the two plans (the first is auto-parameterized and qualifies for trivial plan, whereas the second is not auto-parameterized and requires cost-based optimization), but there is nothing to indicate that one is a scalar aggregate and the other is a vector aggregate.  This is something I would like to see exposed in show plan so I suggested it on Connect.  Anyway, the results of running the two queries show the difference at runtime: The scalar aggregate (no GROUP BY) returns a result of zero, whereas the vector aggregate (with a GROUP BY clause) returns nothing at all.  Returning to our EXISTS query, we could ‘fix’ it by changing the HAVING clause to reject rows where the scalar aggregate returns zero: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) BETWEEN 1 AND 9 ); The query now returns the correct 23 rows: Unfortunately, the execution plan is less efficient now – it has an estimated cost of 0.78 compared to 0.33 for the earlier plans.  Let’s try adding a redundant GROUP BY instead of changing the HAVING clause: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY th.ProductID HAVING COUNT_BIG(*) < 10 ); Not only do we now get correct results (23 rows), this is the execution plan: I like to compare that plan to quantum physics: if you don’t find it shocking, you haven’t understood it properly :)  The simple addition of a redundant GROUP BY has resulted in the EXISTS form of the query being transformed into exactly the same optimal plan we found earlier.  What’s more, in SQL Server 2008 and later, we can replace the odd-looking GROUP BY with an explicit GROUP BY on the empty set: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ); I offer that as an alternative because some people find it more intuitive (and it perhaps has more geek value too).  Whichever way you prefer, it’s rather satisfying to note that the result of the sub-query does not exist for a particular correlated value where a vector aggregate is used (the scalar COUNT aggregate always returns a value, even if zero, so it always ‘EXISTS’ regardless which ProductID is logically being evaluated). The following query forms also produce the optimal plan and correct results, so long as a vector aggregate is used (you can probably find more equivalent query forms): WHERE Clause SELECT p.Name FROM Production.Product AS p WHERE ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) < 10; APPLY SELECT p.Name FROM Production.Product AS p CROSS APPLY ( SELECT NULL FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ) AS ca (dummy); FROM Clause SELECT q1.Name FROM ( SELECT p.Name, cnt = ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) FROM Production.Product AS p ) AS q1 WHERE q1.cnt < 10; This last example uses SUM(1) instead of COUNT and does not require a vector aggregate…you should be able to work out why :) SELECT q.Name FROM ( SELECT p.Name, cnt = ( SELECT SUM(1) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID ) FROM Production.Product AS p ) AS q WHERE q.cnt < 10; The semantics of SQL aggregates are rather odd in places.  It definitely pays to get to know the rules, and to be careful to check whether your queries are using scalar or vector aggregates.  As we have seen, query plans do not show in which ‘mode’ an aggregate is running and getting it wrong can cause poor performance, wrong results, or both. © 2012 Paul White Twitter: @SQL_Kiwi email: [email protected]

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  • Fun with Aggregates

    - by Paul White
    There are interesting things to be learned from even the simplest queries.  For example, imagine you are given the task of writing a query to list AdventureWorks product names where the product has at least one entry in the transaction history table, but fewer than ten. One possible query to meet that specification is: SELECT p.Name FROM Production.Product AS p JOIN Production.TransactionHistory AS th ON p.ProductID = th.ProductID GROUP BY p.ProductID, p.Name HAVING COUNT_BIG(*) < 10; That query correctly returns 23 rows (execution plan and data sample shown below): The execution plan looks a bit different from the written form of the query: the base tables are accessed in reverse order, and the aggregation is performed before the join.  The general idea is to read all rows from the history table, compute the count of rows grouped by ProductID, merge join the results to the Product table on ProductID, and finally filter to only return rows where the count is less than ten. This ‘fully-optimized’ plan has an estimated cost of around 0.33 units.  The reason for the quote marks there is that this plan is not quite as optimal as it could be – surely it would make sense to push the Filter down past the join too?  To answer that, let’s look at some other ways to formulate this query.  This being SQL, there are any number of ways to write logically-equivalent query specifications, so we’ll just look at a couple of interesting ones.  The first query is an attempt to reverse-engineer T-SQL from the optimized query plan shown above.  It joins the result of pre-aggregating the history table to the Product table before filtering: SELECT p.Name FROM ( SELECT th.ProductID, cnt = COUNT_BIG(*) FROM Production.TransactionHistory AS th GROUP BY th.ProductID ) AS q1 JOIN Production.Product AS p ON p.ProductID = q1.ProductID WHERE q1.cnt < 10; Perhaps a little surprisingly, we get a slightly different execution plan: The results are the same (23 rows) but this time the Filter is pushed below the join!  The optimizer chooses nested loops for the join, because the cardinality estimate for rows passing the Filter is a bit low (estimate 1 versus 23 actual), though you can force a merge join with a hint and the Filter still appears below the join.  In yet another variation, the < 10 predicate can be ‘manually pushed’ by specifying it in a HAVING clause in the “q1” sub-query instead of in the WHERE clause as written above. The reason this predicate can be pushed past the join in this query form, but not in the original formulation is simply an optimizer limitation – it does make efforts (primarily during the simplification phase) to encourage logically-equivalent query specifications to produce the same execution plan, but the implementation is not completely comprehensive. Moving on to a second example, the following query specification results from phrasing the requirement as “list the products where there exists fewer than ten correlated rows in the history table”: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) < 10 ); Unfortunately, this query produces an incorrect result (86 rows): The problem is that it lists products with no history rows, though the reasons are interesting.  The COUNT_BIG(*) in the EXISTS clause is a scalar aggregate (meaning there is no GROUP BY clause) and scalar aggregates always produce a value, even when the input is an empty set.  In the case of the COUNT aggregate, the result of aggregating the empty set is zero (the other standard aggregates produce a NULL).  To make the point really clear, let’s look at product 709, which happens to be one for which no history rows exist: -- Scalar aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709;   -- Vector aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709 GROUP BY th.ProductID; The estimated execution plans for these two statements are almost identical: You might expect the Stream Aggregate to have a Group By for the second statement, but this is not the case.  The query includes an equality comparison to a constant value (709), so all qualified rows are guaranteed to have the same value for ProductID and the Group By is optimized away. In fact there are some minor differences between the two plans (the first is auto-parameterized and qualifies for trivial plan, whereas the second is not auto-parameterized and requires cost-based optimization), but there is nothing to indicate that one is a scalar aggregate and the other is a vector aggregate.  This is something I would like to see exposed in show plan so I suggested it on Connect.  Anyway, the results of running the two queries show the difference at runtime: The scalar aggregate (no GROUP BY) returns a result of zero, whereas the vector aggregate (with a GROUP BY clause) returns nothing at all.  Returning to our EXISTS query, we could ‘fix’ it by changing the HAVING clause to reject rows where the scalar aggregate returns zero: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) BETWEEN 1 AND 9 ); The query now returns the correct 23 rows: Unfortunately, the execution plan is less efficient now – it has an estimated cost of 0.78 compared to 0.33 for the earlier plans.  Let’s try adding a redundant GROUP BY instead of changing the HAVING clause: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY th.ProductID HAVING COUNT_BIG(*) < 10 ); Not only do we now get correct results (23 rows), this is the execution plan: I like to compare that plan to quantum physics: if you don’t find it shocking, you haven’t understood it properly :)  The simple addition of a redundant GROUP BY has resulted in the EXISTS form of the query being transformed into exactly the same optimal plan we found earlier.  What’s more, in SQL Server 2008 and later, we can replace the odd-looking GROUP BY with an explicit GROUP BY on the empty set: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ); I offer that as an alternative because some people find it more intuitive (and it perhaps has more geek value too).  Whichever way you prefer, it’s rather satisfying to note that the result of the sub-query does not exist for a particular correlated value where a vector aggregate is used (the scalar COUNT aggregate always returns a value, even if zero, so it always ‘EXISTS’ regardless which ProductID is logically being evaluated). The following query forms also produce the optimal plan and correct results, so long as a vector aggregate is used (you can probably find more equivalent query forms): WHERE Clause SELECT p.Name FROM Production.Product AS p WHERE ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) < 10; APPLY SELECT p.Name FROM Production.Product AS p CROSS APPLY ( SELECT NULL FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ) AS ca (dummy); FROM Clause SELECT q1.Name FROM ( SELECT p.Name, cnt = ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) FROM Production.Product AS p ) AS q1 WHERE q1.cnt < 10; This last example uses SUM(1) instead of COUNT and does not require a vector aggregate…you should be able to work out why :) SELECT q.Name FROM ( SELECT p.Name, cnt = ( SELECT SUM(1) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID ) FROM Production.Product AS p ) AS q WHERE q.cnt < 10; The semantics of SQL aggregates are rather odd in places.  It definitely pays to get to know the rules, and to be careful to check whether your queries are using scalar or vector aggregates.  As we have seen, query plans do not show in which ‘mode’ an aggregate is running and getting it wrong can cause poor performance, wrong results, or both. © 2012 Paul White Twitter: @SQL_Kiwi email: [email protected]

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  • C to C++ Conversion [closed]

    - by Annalyne
    Can someone convert this code to C++, pretty please? :( #include <stdio.h> #include <stdlib.h> #include <time.h> #define WEAPON_ROPE 10 #define WEAPON_REVOLVER 20 #define WEAPON_LEADPIPE 30 #define WEAPON_CANDLESTICK 40 #define WEAPON_KNIFE 50 #define WEAPON_WRENCH 60 #define PEOPLE_MRGREEN 100 #define PEOPLE_MSSCARLET 200 #define PEOPLE_CONLMUSTARD 300 #define PEOPLE_PROFPLUM 400 #define PEOPLE_MISPEACOCK 500 #define PEOPLE_MISWHITE 600 #define PLACE_KITCHEN 1 #define PLACE_HALL 2 #define PLACE_POOLROOM 3 #define PLACE_STUDY 4 #define PLACE_LOUNG 5 #define PLACE_LIBRARY 6 #define PLACE_CONSERVATORY 7 #define PLACE_DINING 8 #define PLACE_BILLIARDS 9 int main() { int die = 0; int players[6][9] = {{0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}}; int allCards[] = {WEAPON_ROPE, WEAPON_REVOLVER, WEAPON_LEADPIPE, WEAPON_CANDLESTICK, WEAPON_CANDLESTICK, WEAPON_KNIFE, WEAPON_WRENCH, PEOPLE_MRGREEN, PEOPLE_MSSCARLET, PEOPLE_CONLMUSTARD, PEOPLE_CONLMUSTARD, PEOPLE_PROFPLUM, PEOPLE_MISPEACOCK, PEOPLE_MISWHITE, PLACE_KITCHEN, PLACE_HALL, PLACE_POOLROOM, PLACE_STUDY, PLACE_LOUNG, PLACE_LIBRARY, PLACE_CONSERVATORY, PLACE_DINING, PLACE_BILLIARDS}; int deckSize = 23; // number of cards in allCards array int count; for (count = 0; count < deckSize; ++count) { printf(", %d", allCards[count]); } // End for // These three array's are so you can put a card back, if need be... int weaponCards[] = {WEAPON_ROPE, WEAPON_REVOLVER, WEAPON_LEADPIPE, WEAPON_CANDLESTICK, WEAPON_CANDLESTICK, WEAPON_KNIFE, WEAPON_WRENCH}; int weaponDeckSize = 7; int peopleCards[] = {PEOPLE_MRGREEN, PEOPLE_MSSCARLET, PEOPLE_CONLMUSTARD, PEOPLE_CONLMUSTARD, PEOPLE_PROFPLUM, PEOPLE_MISPEACOCK, PEOPLE_MISWHITE}; int peopleDeckSize = 7; int placeCards[] = {PLACE_KITCHEN, PLACE_HALL, PLACE_POOLROOM, PLACE_STUDY, PLACE_LOUNG, PLACE_LIBRARY, PLACE_CONSERVATORY, PLACE_DINING, PLACE_BILLIARDS}; int placeDeckSize = 9; srand(clock()); // seed rand() using clock() which gives // the current tick your processor is at... int killer[3]; // no need to initialize yet. killer[0-2] will initialize int deckShuffle = rand() % weaponDeckSize; // picks one number out of the deck killer[0] = weaponCards[deckShuffle]; allCards[deckShuffle] = 0; // Card drawn. No longer exists in deck deckShuffle = rand() % peopleDeckSize; // picks another random card out of the deck killer[1] = peopleCards[deckShuffle]; allCards[deckShuffle + weaponDeckSize] = 0; // Card drawn. No longer exists in deck deckShuffle = rand() % placeDeckSize; // randomly picks the last card needed killer[2] = placeCards[deckShuffle]; allCards[deckShuffle + weaponDeckSize + peopleDeckSize] = 0; // Card drawn. No longer exists in deck int numberOfCards = 0; printf("CLUE\n"); printf("written by John Schintone\n"); printf("Origonal game delvoped by Hasbro\n"); int numberOfPlayers = 0; while ((numberOfPlayers < 3) || (numberOfPlayers > 6)) { printf("How many players are Going to play :\n"); printf("[number] > "); scanf("%d",&numberOfPlayers); // A very fast if statement which only uses integers/char's switch(numberOfPlayers) { case 6: { numberOfCards = 3; } break; case 5: { numberOfCards = 4; } break; case 4: { numberOfCards = 5; } break; case 3: { numberOfCards = 6; } break; default: { printf("You must enter a number between 3 and 6...\n"); } // End default } // End switch } // End while int index1, index2; // Note: ++index1; is faster than index1++; and will almost always // produce better code (index1++ happens after this statement line. // ++index1 increments index1 before this statement line) for (index1 = 0; index1 < numberOfPlayers; ++index1) { printf("Player %d", index1); for (index2 = 0; index2 < numberOfCards; ++index2) { // Remember that allCards[deckShuffle] == 0 because we removed that // card ages ago... works out well, just don't forget you did that : ) while (allCards[deckShuffle] == 0) { deckShuffle = rand() % deckSize; } // End while players[index1][index2] = allCards[deckShuffle]; allCards[deckShuffle] = 0; // Card removed for after loop... printf(", %d", players[index1][index2]); switch(players[index1][index2]) { case WEAPON_ROPE: { } break; // Add more... case PEOPLE_MRGREEN: { } break; // Add more... case PLACE_KITCHEN: { } break; // Add more... default: { printf("Program has caught player %d cheating...", index1); } // End default } // End switch } // End for printf("\n"); } // End for printf("The killer is %d, with the %d, and in the %d \n\n", killer[0], killer[1], killer[2]); printf("Type h for this help... \n"); printf("Type e to escape... \n"); printf("Type r to roll the die... \n"); char command = '\0'; // \0 represents zero, or the null character while (command != 'e') { printf("[one character] > "); scanf("%c", &command); if (command == 'r') { die = rand() % 6 + 1; printf("Your number is: %d \n", die); } // end while if (command == 'h') { printf("Type h for this help... \n"); printf("Type e to escape... \n"); printf("Type r to roll the die... \n"); } // End if printf("\n"); } // End while return(0); // Success. Program worked ok } // End main() Function

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  • Minecraft Style Chunk building problem

    - by David Torrey
    I'm having some problems with speed in my chunk engine. I timed it out, and in its current state it takes a total ~5 seconds per chunk to fill each face's list. I have a check to see if each face of a block is visible and if it is not visible, it skips it and moves on. I'm using a dictionary (unordered map) because it makes sense memorywise to just not have an entry if there is no block. I've tracked my problem down to testing if there is an entry, and accessing an entry if it does exist. If I remove the tests to see if there is an entry in the dictionary for an adjacent block, or if the block type itself is seethrough, it runs within about 2-4 milliseconds. so here's my question: Is there a faster way to check for an entry in a dictionary than .ContainsKey()? As an aside, I tried TryGetValue() and it doesn't really help with the speed that much. If I remove the ContainsKey() and keep the test where it does the IsSeeThrough for each block, it halves the time, but it's still about 2-3 seconds. It only drops to 2-4ms if I remove BOTH checks. Here is my code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Runtime.InteropServices; using OpenTK; using OpenTK.Graphics.OpenGL; using System.Drawing; namespace Anabelle_Lee { public enum BlockEnum { air = 0, dirt = 1, } [StructLayout(LayoutKind.Sequential,Pack=1)] public struct Coordinates<T1> { public T1 x; public T1 y; public T1 z; public override string ToString() { return "(" + x + "," + y + "," + z + ") : " + typeof(T1); } } public struct Sides<T1> { public T1 left; public T1 right; public T1 top; public T1 bottom; public T1 front; public T1 back; } public class Block { public int blockType; public bool SeeThrough() { switch (blockType) { case 0: return true; } return false ; } public override string ToString() { return ((BlockEnum)(blockType)).ToString(); } } class Chunk { private Dictionary<Coordinates<byte>, Block> mChunkData; //stores the block data private Sides<List<Coordinates<byte>>> mVBOVertexBuffer; private Sides<int> mVBOHandle; //private bool mIsChanged; private const byte mCHUNKSIZE = 16; public Chunk() { } public void InitializeChunk() { //create VBO references #if DEBUG Console.WriteLine ("Initializing Chunk"); #endif mChunkData = new Dictionary<Coordinates<byte> , Block>(); //mIsChanged = true; GL.GenBuffers(1, out mVBOHandle.left); GL.GenBuffers(1, out mVBOHandle.right); GL.GenBuffers(1, out mVBOHandle.top); GL.GenBuffers(1, out mVBOHandle.bottom); GL.GenBuffers(1, out mVBOHandle.front); GL.GenBuffers(1, out mVBOHandle.back); //make new list of vertexes for each face mVBOVertexBuffer.top = new List<Coordinates<byte>>(); mVBOVertexBuffer.bottom = new List<Coordinates<byte>>(); mVBOVertexBuffer.left = new List<Coordinates<byte>>(); mVBOVertexBuffer.right = new List<Coordinates<byte>>(); mVBOVertexBuffer.front = new List<Coordinates<byte>>(); mVBOVertexBuffer.back = new List<Coordinates<byte>>(); #if DEBUG Console.WriteLine("Chunk Initialized"); #endif } public void GenerateChunk() { #if DEBUG Console.WriteLine("Generating Chunk"); #endif for (byte i = 0; i < mCHUNKSIZE; i++) { for (byte j = 0; j < mCHUNKSIZE; j++) { for (byte k = 0; k < mCHUNKSIZE; k++) { Random blockLoc = new Random(); Coordinates<byte> randChunk = new Coordinates<byte> { x = i, y = j, z = k }; mChunkData.Add(randChunk, new Block()); mChunkData[randChunk].blockType = blockLoc.Next(0, 1); } } } #if DEBUG Console.WriteLine("Chunk Generated"); #endif } public void DeleteChunk() { //delete VBO references #if DEBUG Console.WriteLine("Deleting Chunk"); #endif GL.DeleteBuffers(1, ref mVBOHandle.left); GL.DeleteBuffers(1, ref mVBOHandle.right); GL.DeleteBuffers(1, ref mVBOHandle.top); GL.DeleteBuffers(1, ref mVBOHandle.bottom); GL.DeleteBuffers(1, ref mVBOHandle.front); GL.DeleteBuffers(1, ref mVBOHandle.back); //clear all vertex buffers ClearPolyLists(); #if DEBUG Console.WriteLine("Chunk Deleted"); #endif } public void UpdateChunk() { #if DEBUG Console.WriteLine("Updating Chunk"); #endif ClearPolyLists(); //prepare buffers //for every entry in mChunkData map foreach(KeyValuePair<Coordinates<byte>,Block> feBlockData in mChunkData) { Coordinates<byte> checkBlock = new Coordinates<byte> { x = feBlockData.Key.x, y = feBlockData.Key.y, z = feBlockData.Key.z }; //check for polygonson the left side of the cube if (checkBlock.x > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x - 1, checkBlock.y, checkBlock.z)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.left); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.left); } //check for polygons on the right side of the cube if (checkBlock.x < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x + 1, checkBlock.y, checkBlock.z)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.right); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.right); } if (checkBlock.y > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x, checkBlock.y - 1, checkBlock.z)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.bottom); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.bottom); } //check for polygons on the right side of the cube if (checkBlock.y < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x, checkBlock.y + 1, checkBlock.z)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.top); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.top); } if (checkBlock.z > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x, checkBlock.y, checkBlock.z - 1)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.back); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.back); } //check for polygons on the right side of the cube if (checkBlock.z < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x, checkBlock.y, checkBlock.z + 1)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.front); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.front); } } BuildBuffers(); #if DEBUG Console.WriteLine("Chunk Updated"); #endif } public void RenderChunk() { } public void LoadChunk() { #if DEBUG Console.WriteLine("Loading Chunk"); #endif #if DEBUG Console.WriteLine("Chunk Deleted"); #endif } public void SaveChunk() { #if DEBUG Console.WriteLine("Saving Chunk"); #endif #if DEBUG Console.WriteLine("Chunk Saved"); #endif } private bool IsVisible(int pX,int pY,int pZ) { Block testBlock; Coordinates<byte> checkBlock = new Coordinates<byte> { x = Convert.ToByte(pX), y = Convert.ToByte(pY), z = Convert.ToByte(pZ) }; if (mChunkData.TryGetValue(checkBlock,out testBlock )) //if data exists { if (testBlock.SeeThrough() == true) //if existing data is not seethrough { return true; } } return true; } private void AddPoly(byte pX, byte pY, byte pZ, int BufferSide) { //create temp array GL.BindBuffer(BufferTarget.ArrayBuffer, BufferSide); if (BufferSide == mVBOHandle.front) { //front face mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); } else if (BufferSide == mVBOHandle.right) { //back face mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.top) { //left face mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.bottom) { //right face mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); } else if (BufferSide == mVBOHandle.front) { //top face mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.back) { //bottom face mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ + 1) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ + 1) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ + 1) }); } } private void BuildBuffers() { #if DEBUG Console.WriteLine("Building Chunk Buffers"); #endif GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.front); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.front.Count), mVBOVertexBuffer.front.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.back); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.back.Count), mVBOVertexBuffer.back.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.left); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.left.Count), mVBOVertexBuffer.left.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.right); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.right.Count), mVBOVertexBuffer.right.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.top); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.top.Count), mVBOVertexBuffer.top.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.bottom); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.bottom.Count), mVBOVertexBuffer.bottom.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer,0); #if DEBUG Console.WriteLine("Chunk Buffers Built"); #endif } private void ClearPolyLists() { #if DEBUG Console.WriteLine("Clearing Polygon Lists"); #endif mVBOVertexBuffer.top.Clear(); mVBOVertexBuffer.bottom.Clear(); mVBOVertexBuffer.left.Clear(); mVBOVertexBuffer.right.Clear(); mVBOVertexBuffer.front.Clear(); mVBOVertexBuffer.back.Clear(); #if DEBUG Console.WriteLine("Polygon Lists Cleared"); #endif } }//END CLASS }//END NAMESPACE

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  • Finding anagaram(s) of dictionary words

    - by Codenotguru
    How can I take an input word (or sequence of letters) and output a word from a dictionary that contains exactly those letters? Does java has an English dictionary class (list of words) that I can use, or are there open source implementations of this? How can I optimize my code if this needs to be done repeatedly?

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  • Delphi - How do I split a string into an array of strings based on a delimiter?

    - by Ryan
    Hello all, I'm trying to find a Delphi function that will split an input string into an array of strings based on a delimiter. I've found a lot on Google, but all seem to have their own issues and I haven't been able to get any of them to work. I just need to split a string like: "word:doc,txt,docx" into an array based on ':'. The result would be ['word', 'doc,txt,docx']. Does anyone have a function that they know works? Thank you

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  • Comparing strings with user-created string class

    - by meepz
    Basically, I created my own string class, mystring.h and mystring.c. What I want to do is write a function that compares two "strings" and then returns 1 first word is larger than the second, the opposite if word 2 is larger than word 1, and 0 if the two words are equal. What I have so far is this: int compareto(void * S1, void * S2){ String s1 = (String S1); String s2 = (String S2); int i, cs1 = 0, cs2 = 0; //cs1 is count of s1, cs2 is count of s2 while(s1->c[i] != '\0'){ //basically, while there is a word if(s1->c[i] < s2->c[i]) // if string 1 char is less than string 2 char cs2++; //add to string 2 count else (s1->c[i] > s2->c[i]) //vice versa cs1++; i++; } for my return I basically have if(cs1>cs2){ return 1; } else if(cs2 > cs1){ return 2; } return 0; here is mystring.h typedef struct mystring { char * c; int length; int (*sLength)(void * s); char (*charAt)(void * s, int i); int (*compareTo)(void * s1, void * s2); struct mystring * (*concat)(void * s1, void * s2); struct mystring * (*subString)(void * s, int begin, int end); void (*printS)(void * s); } string_t; typedef string_t * String; This does what I want, but only for unspecified order. What I want to do is search through my linked list for the last name. Ex. I have two entries in my linked list, smith and jones; Jones will be output as greater than smith, but alphabetically it isnt. (I'm using this to remove student entries from a generic link list I created) Any suggestions, all of my google searches involve using the library, so I've had no luck)

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