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  • Android Alert Dialog Extract User Choice Radio Button?

    - by kel196
    Apologies for any coding ignorance, I am a beginner and am still learning! I am creating a quiz app which reads questions off a SQL database and plots them as points on a google map. As the user clicks each point, an alert dialog appears with radio buttons to answer some question. My radiobuttons are in CustomItemizedOverlay file and when I click submit, I want to be able to send the user choice back to the database, save it and return to the user if their answer is correct. My question is this, how do I pass the user choice out once the submit button has been clicked? I tried making a global variable to read what was selected to no avail. Any suggestions would be appreciated! If I need to post any other code, please ask and I will do so ASAP! package uk.ac.ucl.cege.cegeg077.uceskkw; import java.util.ArrayList; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.graphics.drawable.Drawable; import android.widget.Toast; import com.google.android.maps.ItemizedOverlay; import com.google.android.maps.OverlayItem; public class CustomItemizedOverlay2 extends ItemizedOverlay<OverlayItem> { private ArrayList<OverlayItem> mapOverlays = new ArrayList<OverlayItem>(); private Context context; public CustomItemizedOverlay2(Drawable defaultMarker) { super(boundCenterBottom(defaultMarker)); } public CustomItemizedOverlay2(Drawable defaultMarker, Context context) { this(defaultMarker); this.context = context; } @Override protected OverlayItem createItem(int i) { return mapOverlays.get(i); } @Override public int size() { return mapOverlays.size(); } @Override protected boolean onTap(int index) { OverlayItem item = mapOverlays.get(index); // gets the snippet from ParseKMLAndDisplayOnMap and splits it back into // a string. final CharSequence allanswers[] = item.getSnippet().split("::"); AlertDialog.Builder dialog = new AlertDialog.Builder(context); dialog.setIcon(R.drawable.easterbunnyegg); dialog.setTitle(item.getTitle()); dialog.setSingleChoiceItems(allanswers, -1, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { Toast.makeText(context, "You have selected " + allanswers[whichButton], Toast.LENGTH_SHORT).show(); } }); dialog.setPositiveButton(R.string.button_submit, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); // int selectedPosition = ((AlertDialog) // dialog).getListView().getCheckedItemPosition(); Toast.makeText(context, "hi!", Toast.LENGTH_SHORT) .show(); } }); dialog.setNegativeButton(R.string.button_close, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); // on cancel button action } }); AlertDialog question = dialog.create(); question.show(); return true; } public void addOverlay(OverlayItem overlay) { mapOverlays.add(overlay); this.populate(); } }

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  • Consing lists with user-defined type in Haskell

    - by user1319603
    I have this type I defined myself: data Item = Book String String String Int -- Title, Author, Year, Qty | Movie String String String Int -- Title, Director, Year, Qty | CD String String String Int deriving Show -- Title, Artist, Year, Qty I've created an empty list all_Items = [] With the following function I am trying to insert a new book of type Item (Book) into the all_Items addBook all_Items = do putStrLn "Enter the title of the book" tit <- getLine putStrLn "Enter the author of the book" aut <- getLine putStrLn "Enter the year this book was published" yr <- getLine putStrLn "Enter quantity of copies for this item in the inventory" qty <- getLine Book tit aut yr (read qty::Int):all_Items return(all_Items) I however am receiving this error: Couldn't match expected type `IO a0' with actual type `[a1]' The error points to the line where I am using the consing operator to add the new book to the list. I can gather that it is a type error but I can't figure out what it is that I am doing wrong and how to fix it. Thanks in Advance!

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  • Replicating Java's DecimalFormat in C#

    - by Frank Krueger
    I am trying to replicate a subset of Java's DecimalFormat class. Below is what I've come up with. Does this look right to everyone? public class DecimalFormat : NumberFormat { int _maximumFractionDigits; int _minimumFractionDigits; string _format; void RebuildFormat () { _format = "{0:0."; _format += new string ('0', _minimumFractionDigits); if (_maximumFractionDigits > _minimumFractionDigits) { _format += new string ('#', _maximumFractionDigits - _minimumFractionDigits); } _format += "}"; } public override string format (object value) { return string.Format (_format, value); } public override void setMaximumFractionDigits (int n) { _maximumFractionDigits = n; RebuildFormat (); } public override void setMinimumFractionDigits (int n) { _minimumFractionDigits = n; RebuildFormat (); } public override void setGroupingUsed (bool g) { } public static NumberFormat getInstance () { return new DecimalFormat (); } }

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  • Calculate pixels within a polygon

    - by DoomStone
    In an assignment for school do we need to do some image recognizing, where we have to find a path for a robot. So far have we been able to find all the polygons in the image, but now we need to generate a pixel map, that be used for an astar algorithm later. We have found a way to do this, show below, but the problem is that is very slow, as we go though each pixel and test if it is inside the polygon. So my question is, are there a way that we can generate this pixel map faster? We have a list of cordinates for the polygon private List<IntPoint> hull; The fuction "getMap" is called to get the pixel map public Point[] getMap() { List<Point> points = new List<Point>(); lock (hull) { Rectangle rect = getRectangle(); for (int x = rect.X; x <= rect.X + rect.Width; x++) { for (int y = rect.Y; y <= rect.Y + rect.Height; y++) { if (inPoly(x, y)) points.Add(new Point(x, y)); } } } return points.ToArray(); } Get Rectangle is used to limit the search, se we don't have to go thoug the whole image public Rectangle getRectangle() { int x = -1, y = -1, width = -1, height = -1; foreach (IntPoint item in hull) { if (item.X < x || x == -1) x = item.X; if (item.Y < y || y == -1) y = item.Y; if (item.X > width || width == -1) width = item.X; if (item.Y > height || height == -1) height = item.Y; } return new Rectangle(x, y, width-x, height-y); } And atlast this is how we check to see if a pixel is inside the polygon public bool inPoly(int x, int y) { int i, j = hull.Count - 1; bool oddNodes = false; for (i = 0; i < hull.Count; i++) { if (hull[i].Y < y && hull[j].Y >= y || hull[j].Y < y && hull[i].Y >= y) { try { if (hull[i].X + (y - hull[i].X) / (hull[j].X - hull[i].X) * (hull[j].X - hull[i].X) < x) { oddNodes = !oddNodes; } } catch (DivideByZeroException e) { if (0 < x) { oddNodes = !oddNodes; } } } j = i; } return oddNodes; }

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  • print integer and array from file android

    - by vik
    i want to open a file and then calculate the integer and array value from file and print on the screen. i tried this but not working @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); TextView av = new TextView(this); setContentView(av); try { String i = "abc.xyz"; InputStream in = assets.open(i); try { DataInputStream din = new DataInputStream(in); int value = din.readInt(); // print value on screen int[] arry = new int[1]; // print arry on screen how to do it int arry[1] = din.readInt(); } } finally { in.close(); } } catch (IOException e) { throw new PuzzleIOException(e); } av.setText(size); }

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  • java - unwanted object overwriting

    - by gosling
    Hello everyone! I'm trying to make a program that solves the logic wheels puzzle. I construct the root node and I try to produce the different child-nodes that are produced by making different moves of the wheels. The problem is that while I try to produce the children, the root node is overwrited,and everything is messed-up and I really don't know why. Here you can find the puzzle logic wheels. I represent the wheels as 3x3 arrays. Here is the code that implements the moves: public Node turn_right(Node aNode, int which_wheel) { Node newNode = new Node(aNode.getYellow_wheel(),aNode.getBlue_wheel(),aNode.getGreen_wheel()); int[][] yellow = new int[3][3]; int[][] blue = new int[3][3]; int[][] green = new int[3][3]; if(which_wheel==0) //turn yellow wheel of this node to right { yellow[1][0] = newNode.getYellow_wheel()[0][0]; yellow[2][0] = newNode.getYellow_wheel()[1][0]; yellow[2][1] = newNode.getYellow_wheel()[2][0]; yellow[2][2] = newNode.getYellow_wheel()[2][1]; yellow[1][2] = newNode.getYellow_wheel()[2][2]; yellow[0][2] = newNode.getYellow_wheel()[1][2]; yellow[0][1] = newNode.getYellow_wheel()[0][2]; yellow[0][0] = newNode.getYellow_wheel()[0][1]; blue = newNode.getBlue_wheel(); blue[1][0] = newNode.getYellow_wheel()[1][2]; blue[2][0] = newNode.getYellow_wheel()[2][2]; green = newNode.getGreen_wheel(); } else if(which_wheel == 1)// turn blue wheel of this node to right { blue[1][0] = newNode.getBlue_wheel()[0][0]; blue[2][0] = newNode.getBlue_wheel()[1][0]; blue[2][1] = newNode.getBlue_wheel()[2][0]; blue[2][2] = newNode.getBlue_wheel()[2][1]; blue[1][2] = newNode.getBlue_wheel()[2][2]; blue[0][2] = newNode.getBlue_wheel()[1][2]; blue[0][1] = newNode.getBlue_wheel()[0][2]; blue[0][0] = newNode.getBlue_wheel()[0][1]; yellow = newNode.getYellow_wheel(); yellow[0][2] = newNode.getBlue_wheel()[0][0]; yellow[1][2] = newNode.getBlue_wheel()[1][0]; green = newNode.getGreen_wheel(); green[1][0] = newNode.getBlue_wheel()[1][2]; green[2][0] = newNode.getBlue_wheel()[2][2]; } else if (which_wheel == 2)//turn green wheel of this node to right { green[0][0] = newNode.getGreen_wheel()[0][1]; green[0][1] = newNode.getGreen_wheel()[0][2]; green[0][2] = newNode.getGreen_wheel()[1][2]; green[1][2] = newNode.getGreen_wheel()[2][2]; green[2][2] = newNode.getGreen_wheel()[2][1]; green[2][1] = newNode.getGreen_wheel()[2][0]; green[2][0] = newNode.getGreen_wheel()[1][0]; green[1][0] = newNode.getGreen_wheel()[0][0]; yellow = newNode.getYellow_wheel(); blue = newNode.getBlue_wheel(); blue[0][2] = newNode.getGreen_wheel()[0][0]; blue[1][2] = newNode.getGreen_wheel()[1][0]; } newNode= new Node(yellow,blue,green); return newNode; } There is another function, like this one that does the oposite:it turns the wheels to left. My problem is that I do not want object's aNode tables to be overwritten. Thank you very much.

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  • How do I send the mutable string to the NSTextField properly?

    - by Merle
    So I have all this code that I have debugged and it seems to be fine. I made a mutable string and for some reason I can not get it to be displayed on my label. the debugger says "2010-04-22 22:50:26.126 Fibonacci[24836:10b] * -[NSTextField setString:]: unrecognized selector sent to instance 0x130150" What is wrong with this? When I just send the string to NSLog, it comes out fine. here's all my code, any help would be appreciated. "elementNum" is a comboBox and "display" is a Label. Thanks #import "Controller.h" @implementation Controller - (IBAction)computeNumber:(id)sender { int x = 1; int y = 1; NSMutableString *numbers = [[NSMutableString alloc] init]; [numbers setString:@"1, 1,"]; int num = [[elementNum objectValueOfSelectedItem]intValue]; int count = 1; while (count<=num) { int z = y; y+=x; x=z; [numbers appendString:[NSString stringWithFormat:@" %d,", y]]; count++; } [display setString:numbers]; NSLog(numbers); } @end `

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  • C# iterator is executed twice when composing two IEnumerable methods

    - by achristoph
    I just started learning about C# iterator but got confused with the flow of the program after reading the output of the program. The foreach with uniqueVals seems to be executed twice. My understanding is that the first few lines up to the line before "Nums in Square: 3" should not be there. Can anyone help to explain why this happens? The output is: Unique: 1 Adding to uniqueVals: 1 Unique: 2 Adding to uniqueVals: 2 Unique: 2 Unique: 3 Adding to uniqueVals: 3 Nums in Square: 3 Unique: 1 Adding to uniqueVals: 1 Square: 1 Number returned from Unique: 1 Unique: 2 Adding to uniqueVals: 2 Square: 2 Number returned from Unique: 4 Unique: 2 Unique: 3 Adding to uniqueVals: 3 Square: 3 Number returned from Unique: 9 static class Program { public static IEnumerable<T> Unique<T>(IEnumerable<T> sequence) { Dictionary<T, T> uniqueVals = new Dictionary<T, T>(); foreach (T item in sequence) { Console.WriteLine("Unique: {0}", item); if (!uniqueVals.ContainsKey(item)) { Console.WriteLine("Adding to uniqueVals: {0}", item); uniqueVals.Add(item, item); yield return item; Console.WriteLine("After Unique yield: {0}", item); } } } public static IEnumerable<int> Square(IEnumerable<int> nums) { Console.WriteLine("Nums in Square: {0}", nums.Count()); foreach (int num in nums) { Console.WriteLine("Square: {0}", num); yield return num * num; Console.WriteLine("After Square yield: {0}", num); } } static void Main(string[] args) { var nums = new int[] { 1, 2, 2, 3 }; foreach (int num in Square(Unique(nums))) Console.WriteLine("Number returned from Unique: {0}", num); Console.Read(); } }

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  • Output is different for R-value and L-value. Why?

    - by Leonid Volnitsky
    Can someone explain to me why output for R-value is different from L-value? #include <iostream> #include <vector> using namespace std; template<typename Ct> struct ct_wrapper { Ct&& ct; // R or L ref explicit ct_wrapper(Ct&& ct) : ct(std::forward<Ct>(ct)) { std::cout << this->ct[1];}; }; int main() { // L-val vector<int> v{1,2,3}; ct_wrapper<vector<int>&> lv(v); cout << endl << lv.ct[0] << lv.ct[1] << lv.ct[2] << endl; // R-val ct_wrapper<vector<int>&&> rv(vector<int>{1,2,3}); cout << endl << rv.ct[0] << rv.ct[1] << rv.ct[2] << endl; } Output (same for gcc48 and clang32): 2 123 2 003

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  • Expand chaining hashtable. Errors on code.

    - by FILIaS
    Expanding a hashtable with linked lists there are some errors and warnings. I wanna make sure that the following code is right (expand method) and find out what happens that raise these warnings/errors typedef struct { int length; struct List *head; struct List *tail; } HashTable; //resolving collisions using linked lists - chaining typedef struct { char *number; char *name; int time; struct List *next; }List; //on the insert method i wanna check hashtable's size, //if it seems appropriate there is the following code: //Note: hashtable variable is: Hashtable * ...... hashtable = expand(hashtable,number,name,time); /**WARNING**:assignment makes pointer from integer without a cast*/ HashTable* expand( HashTable* h ,char number[10],char* name,int time) /**error**: conflicting types for ‘expand’ previous implicit declaration of ‘expand’ was here*/ { HashTable* new; int n; clientsList *node,*next; PrimesIndex++; int new_size= primes[PrimesIndex]; /* double the size,odd length */ if (!(new=malloc((sizeof( List*))*new_size))) return NULL; for(n=0; n< h->length; ++n) { for(node=h[n].head; node; node=next) { add (&new, node->number, node->name,node->time); next=node->next;//// free(node); } } free(h); return new; }

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  • How can this code throw a NullReferenceException?

    - by Davy8
    I must be going out of my mind, because my unit tests are failing because the following code is throwing a null ref exception: int pid = 0; if (parentCategory != null) { Console.WriteLine(parentCategory.Id); pid = parentCategory.Id; } The line that's throwing it is: pid = parentCategory.Id; The console.writeline is just to debug in the NUnit GUI, but that outputs a valid int. Edit: It's single-threaded so it can't be assigned to null from some other thread, and the fact the the Console.WriteLine successfully prints out the value shows that it shouldn't throw. Edit: Relevant snippets of the Category class: public class Category { private readonly int id; public Category(Category parent, int id) { Parent = parent; parent.PerformIfNotNull(() => parent.subcategories.AddIfNew(this)); Name = string.Empty; this.id = id; } public int Id { get { return id; } } } Well if anyone wants to look at the full code, it's on Google Code at http://code.google.com/p/chefbook/source/checkout I think I'm going to try rebooting the computer... I've seen pretty weird things fixed by a reboot. Will update after reboot. Update: Mystery solved. Looks like NUnit shows the error line as the last successfully executed statement... Copy/pasted test into new console app and ran in VS showed that it was the line after the if statement block (not shown) that contained a null ref. Thanks for all the ideas everyone. +1 to everyone that answered.

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  • Web Services in Blackberry

    - by Farhan
    Hi, i am working on CallLogs Sync Application in Blackberry and partially i have done it, one point that i didn't understand is how to add information to CallLogs. I have retrieved information from CallLogs and Store on Server but now i retrieved information from Server but how to add info to CallLogs didn't come in my mind as i retrieved all the information in Strings from Server and PhoneCallLog Constructor look like this: PhoneCallLog call = new PhoneCallLog(Date,int Type,int Duration,int Status,participantID participant,String Notes); Please tell me as soon as Possible, i will be very thankful to you.

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  • Formula to draw pyramid of circles

    - by terence6
    I'm trying to create a pyramid of circles to my game, looking similar to this : But I can't make it print properly. Constantly I'm getting really strange spirals but nothing close to this. Can anyone give me some tip on proper formula ? My window is 600x600, base of pyramid is 8 . fields = new Field[BASE*(BASE/2)+4]; int line_count = BASE; int line_tmp = line_count; for(int i=0; i< fields.length; i++){ for( int j=line_tmp; j <= line_count; j++){ fields[i] = new Field(0, (150+(line_tmp*5)),(600+line_tmp*5)); } line_count--; line_tmp = line_count; }

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  • sql server swap data between rows problem

    - by AmRoSH
    I was asking b4 about swaping query to swap data between rows in same table and i got that qurey ALTER PROCEDURE [dbo].[VehicleReservationsSwap] -- Add the parameters for the stored procedure here (@FirstVehicleID int, @secondVehicleID int, @WhereClause nvarchar(2000)) AS BEGIN Create Table #Temp ( VehicleID int ,VehicleType nvarchar(100) ,JoinId int ) DECLARE @SQL varchar(8000) SET @SQL ='Insert into #Temp (VehicleID,VehicleType,JoinId) SELECT VehicleID,VehicleType,CASE WHEN VehicleID = ' + Cast(@FirstVehicleID as varchar(10)) + ' then ' + Cast(@secondVehicleID as varchar(10)) + ' ELSE ' + Cast(@FirstVehicleID as varchar(10)) + ' END AS JoinId FROM Reservations WHERE VehicleID in ( ' + Cast(@FirstVehicleID as varchar(10)) + ' , ' + Cast(@secondVehicleID as varchar(10)) + ' )' + @WhereClause EXEC(@SQL) --swap values UPDATE y SET y.VehicleID = #Temp.VehicleID ,y.VehicleType = #Temp.VehicleType FROM Reservations y INNER JOIN #Temp ON y.VehicleID = #Temp.JoinId WHERE y.VehicleID in (@FirstVehicleID,@secondVehicleID) Drop Table #Temp END this query take 2 parameters and swaping all rows returned for each parameter. the problem is the query swaps just if each parameter (forign key) has values I need to make swaping in case if one of them has no vlue. I hope if some one can help me in that . Thanks,

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  • Select columns from join table only without requiring a join

    - by Kent Boogaart
    Given these tables: create table Orders ( Id INT IDENTITY NOT NULL, primary key (Id) ) create table Items ( Id INT IDENTITY NOT NULL, primary key (Id) ) create table OrdersItems ( OrderId INT not null, ItemId INT not null, primary key (OrderId, ItemId) ) Is it possible to use HQL/criteria API to contruct a query that results in the following SQL: SELECT [OrderId], [ItemId] FROM [OrdersItems] I've tried both of these approaches: var hqlResults = session .CreateQuery("select order.id, item.id from Order order inner join order.Items item") .List(); var criteriaResults = session .CreateCriteria<Order>() .CreateAlias("Items", "item", NHibernate.SqlCommand.JoinType.None) .SetProjection(Projections.Property("id"), Projections.Property("item.id")) .List(); But both approaches insist on generating a join (or fail because the join isn't present, in using criteria), resulting in SQL such as: select order.Id, item.Id from Orders order inner join OrdersItems ordersItems on order.Id = ordersItems.ArticleId inner join Items item on ordersItems.CategoryId = item.Id Is there any way to have NHibernate generate a query that selects columns only from the join table, without requiring a join?

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  • How to debug when CakePHP Model::save() doesn't attempt an INSERT

    - by RyOnLife
    I am having a bear of a time saving the simplest record from a model called ItemView: if($this->save($this->data)) { echo 'worked'; } else { echo 'failed'; } Where $this-data is: Array ( [ItemView] => Array ( [list_id] => 1 [user_id] => 1 ) ) And my table is: CREATE TABLE IF NOT EXISTS `item_views` ( `id` int(11) NOT NULL auto_increment, `list_id` int(11) NOT NULL, `user_id` int(11) default NULL, `user_ip` int(10) unsigned default NULL, `created` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 ROW_FORMAT=FIXED AUTO_INCREMENT=1 ; Looking at the query dump in debug mode, Cake isn't even attempting an INSERT, so I have no idea how to debug. Any help would be appreciated.

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  • Segmenting and masking all shades of red from an image using opencv

    - by vrinda
    I am trying to segment all shades of red form an image using hue saturation values and use InRangeS function to create a mask which should have all red areas whitened and all others blacked(a new 1 channel image). Thwn Inpaint them to kind of obscure the segmented portions. My code is as given. However I am unable to get an output image, it doesnt segment the desired color range. Any pointers on my approach and why it isnt working. ? using namespace std; int main() { IplImage *img1=cvLoadImage("/home/techrascal/projects/test1/image2.jpeg"); //IplImage *img3; IplImage *imghsv; IplImage *img4; CvSize sz=cvGetSize(img1); imghsv=cvCreateImage(sz,IPL_DEPTH_8U,3); img4=cvCreateImage(sz,IPL_DEPTH_8U,1); int width = img1->width; int height = img1->height; int bpp = img1->nChannels; cvNamedWindow("original", 1); cvNamedWindow("hsv",1); cvNamedWindow("Blurred",1); int r,g,b; // create inpaint mask: img 4 will behave as mask cvCvtColor(img1,imghsv,CV_BGR2HSV); CvScalar hsv_min = cvScalar(0, 0, 0, 0); CvScalar hsv_max = cvScalar(255, 0, 0, 0); //cvShowImage("hsv",imghsv); cvInRangeS( imghsv, hsv_min, hsv_max, img4 ); cvInpaint(img1, img4, img1, 3,CV_INPAINT_NS ); cvShowImage("Blurred",img1); cvReleaseImage(&img1); cvReleaseImage(&imghsv); cvReleaseImage(&img4); //cvReleaseImage(&img3); char d=cvWaitKey(10000); cvDestroyAllWindows(); return 0;}

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  • How to compute the dot product?

    - by WizardOfOdds
    I have the following piece of pseudo-C/Java/C# code: int a[]= { 30, 20 }; int b[] = { 40, 50 }; int c[] = {12, 12}; How do I compute the sign of the dot-product AB . AC? I'm only interested in the sign, so I have: boolean signABxAC = ? Now concretely what do I write to get the sign of the dot-product AB . AC?

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  • Basic Custom String Class for C++

    - by wdow88
    Hey all, I'm working on building my own string class with very basic functionality. I am having difficulty understand what is going on with the basic class that I have define, and believe there is some sort of error dealing with the scope occurring. When I try to view the objects I created, all the fields are described as (obviously bad pointer). Also, if I make the data fields public or build an accessor method, the program crashes. For some reason the pointer for the object is 0xccccccccc which points to no where. How can a I fix this? Any help/comments are much appreciated. //This is a custom string class, so far the only functions are //constructing and appending #include<iostream> using namespace std; class MyString1 { public: MyString1() { //no arg constructor char *string; string = new char[0]; string[0] ='\0'; std::cout << string; size = 1; } //constructor receives pointer to character array MyString1(char* chars) { int index = 0; //Determine the length of the array while (chars[index] != NULL) index++; //Allocate dynamic memory on the heap char *string; string = new char[index+1]; //Copy the contents of the array pointed by chars into string, the char array of the object for (int ii = 0; ii < index; ii++) string[ii] = chars[ii]; string[index+1] = '\0'; size = index+1; } MyString1 append(MyString1 s) { //determine new size of the appended array and allocate memory int newsize = s.size + size; MyString1 MyString2; char *newstring; newstring = new char[newsize+1]; int index = 0; //load the first string into the array while (string[index] != NULL) { newstring[index] = string[index]; index++; } //load the second string while (s.string[index] != NULL) { newstring[index] = s.string[index]; index++; } //null terminate newstring[newsize+1] = '\0'; delete string; //generate the object for return MyString2.string=newstring; MyString2.size=newsize; return MyString2; } private: char *string; int size; }; int main() { MyString1 string1; MyString1 string2("Hello There"); MyString1 string3("Buddy"); string2.append(string3); return 0; }

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  • c++ warning: address of local variable

    - by chnet
    int * ref () { int tmp = 100; return &tmp; } int main () { int * a = ref(); cout << *a << endl; } I know the function ref () is allocated stack space. It will get destroyed as soon as the function exits. So the complier will give warning information. But my question is why the returning result is still correct.

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  • Object does not exist after constructor?

    - by openbas
    Hello, I have a constructor that looks like this (in c++): Interpreter::Interpreter() { tempDat == new DataObject(); tempDat->clear(); } the constructor of dataObject does absolutely nothing, and clear does this: bool DataObject::clear() { //clear the object if (current_max_id > 0) { indexTypeLookup.clear(); intData.clear(); doubleData.clear(); current_max_id = 0; } } Those members are defined as follows: std::map<int, int> indexTypeLookup; std::map<int, int> intData; std::map<int, double> doubleData; Now the strange thing is that I'm getting a segfault on tempDat-clear(); gdb says tempDat is null. How is that possible? The constructor of tempDat cannot fail, it looks like this: DataObject::DataObject() : current_max_id(0) { } I know there are probably better way's of making such a data structure, but I really like to know where this segfault problem is coming from..

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  • I'd like to know why a function executes fine when called from x but not when called from y

    - by Roland
    When called from archive(), readcont(char *filename) executes fine! Called from runoptions() though, it fails to list the files "archived"! why is this? The program must run in terminal. Use -h as a parameter to view the usage. This program is written to "archive" text files into ".rldzip" files. readcont( char *x) should show the files archived in file (*x) a) Successful call Use the program to archive 3 text files: rldzip.exe a.txt b.txt c.txt FILEXY -a archive() will call readcont and it will work showing the files archived after the binary FILEXY will be created. b) Unsuccessful call After the file is created, use: rldzip.exe FILEXY.rldzip -v You can see that the function crashes! I'd like to know why is this happening! /* Sa se scrie un program care: a) arhiveaza fisiere b) dezarhiveaza fisierele athivate */ #include<stdio.h> #include<stdlib.h> #include<conio.h> #include<string.h> struct content{ char *text; char *flname; }*arc; FILE *f; void readcont(char *x){ FILE *p; if((p = fopen(x, "rb")) == NULL){ perror("Critical error: "); exit(EXIT_FAILURE); } content aux; int i; fread(&i, sizeof(int), 1, p); printf("\nFiles in %s \n\n", x); while(i-- >1 && fread(&aux, sizeof(struct content), 1, p) != 0) printf("%s \n", aux.flname); fclose(p); printf("\n\n"); } void archive(int argc, char **argv){ int i; char inttext[5000], textline[1000]; //Allocate dynamic memory for the content to be archived! arc = (content*)malloc(argc * sizeof(content)); for(i=1; i< argc; i++) { if((f = fopen(argv[i], "r")) == NULL){ printf("%s: ", argv[i]); perror(""); exit(EXIT_FAILURE); } while(!feof(f)){ fgets(textline, 5000, f); strcat(inttext, textline); } arc[i-1].text = (char*)malloc(strlen(inttext) + 1); strcpy(arc[i-1].text, inttext); arc[i-1].flname = (char*)malloc(strlen(argv[i]) + 1); strcpy(arc[i-1].flname, argv[i]); fclose(f); } char *filen; filen=(char*)malloc(strlen(argv[argc])+1+7); strcpy(filen, argv[argc]); strcat(filen, ".rldzip"); f = fopen(filen, "wb"); fwrite(&argc, sizeof(int), 1, f); fwrite(arc, sizeof(content), argc, f); fclose(f); printf("Success! "); for(i=1; i< argc; i++) { (i==argc-1)? printf("and %s ", argv[i]) : printf("%s ", argv[i]); } printf("compressed into %s", filen); readcont(filen); free(filen); } void help(char *v){ printf("\n\n----------------------RLDZIP----------------------\n\nUsage: \n\n Archive n files: \n\n%s $file[1] $file[2] ... $file[n] $output -a\n\nExample:\n%s a.txt b.txt c.txt output -a\n\n\n\nView files:\n\n %s $file.rldzip -v\n\nExample:\n %s fileE.rldzip -v\n\n", v, v, v, v); } void runoptions(int c, char **v){ int i; if(c < 2){ printf("Arguments missing! Use -h for help"); } else{ for(i=0; i<c; i++) if(strcmp(v[i], "-h") == 0){ help(v[0]); exit(2); } for(i=0; i<c; i++) if(strcmp(v[i], "-v") == 0){ if(c != 3){ printf("Arguments misused! Use -h for help"); exit(2); } else { printf("-%s-", v[1]); readcont(v[1]); } } } if(strcmp(v[c-1], "-a") == 0) archive(c-2, v); } main(int argc, char **argv) { runoptions(argc, argv); }

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  • How do I use Some/None Options in this F# example?

    - by Phobis
    I am new to F# and I have this code: if s.Contains("-") then let x,y = match s.Split [|'-'|] with | [|a;b|] -> int a, int b | _ -> 0,0 Notice that we validate that there is a '-' in the string before we split the string, so the match is really unnecessary. Can I rewrite this with Options? I changed this code, it was originally this (but I was getting a warning): if s.Contains("-") then let [|a;b|] = s.Split [|'-'|] let x,y = int a, int b NOTE: I am splitting a range of numbers (range is expressed in a string) and then creating the integer values that represent the range's minimum and maximum.

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  • dangling pointer, reason for value change after free()?

    - by Aman Jain
    In the following code segment, after free(x), why does y becomes 0? As per my understanding, the memory in the heap that was being pointed to by x, and is still being pointed by y, hasn't been allocated to someone else, so how can it change to 0? And moreover, I don't think it is free(x) that changed it to 0. Any comments? #include <stdio.h> int main ( int argc, char *argv[] ) { int *y = NULL; int *x = NULL; x = malloc(4); *x = 5; y = x; printf("[%d]\n", *y); //prints 5 free(x); printf("[%d]\n", *y); //why doesn't print 5?, prints 0 instead return 0; }

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