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  • Java How to get exact tile location in random tile engine

    - by SYNYST3R1
    I am using the slick2d library. I want to know how to get the exact tile location so when I click on a tile it only changes that tile and not every tile on the screen. My tile generation class public Image[] tiles = new Image[3]; public int width, height; public int[][] index; public Image grass, dirt, selection; boolean selected; int mouseX, mouseY; public void init() throws SlickException { grass = new Image("assets/tiles/grass.png"); dirt = new Image("assets/tiles/dirt.png"); selection = new Image("assets/tiles/selection.png"); tiles[0] = grass; tiles[1] = dirt; width = 50; height = 50; index = new int[width][height]; Random rand = new Random(); for (int x = 0; x < width; x++) { for (int y = 0; y < height; y++) { index[x][y] = rand.nextInt(2); } } } public void update(GameContainer gc) { Input input = gc.getInput(); mouseX = input.getMouseX(); mouseY = input.getMouseY(); if(input.isMouseButtonDown(Input.MOUSE_LEFT_BUTTON)) { selected = true; } else{ selected = false; } } public void render() { for (int x = 0; x < width; x++) { for (int y = 0; y < height; y++) { tiles[index[x][y]].draw(x * 64, y *64); if(IsMouseInsideTile(x, y)) selection.draw(x * 64, y * 64); } } } public boolean IsMouseInsideTile(int x, int y) { return (mouseX >= x * 64 && mouseX <= (x + 1) * 64 && mouseY >= y * 64 && mouseY <= (y + 1) * 64); } I have tried a couple different ways to change the tile I am clicking on, but I don't understand how to do it.

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  • Import? Initialize? what do to?

    - by Jeremy B
    I'm working on homework and I'm close but I am having an issue. I just learned how to work with packages in eclipse so I have a class that is importing another class from a package (I think I said that right) The main prompts the user to enter an integer between -100 and 100 and I am having an issue with validating it. I know the issue is where I'm importing I'm just unsure the direction I need to go to fix it. This is a section of my main code. (my issue starts with the last couple lines if you want to skip ahead) import myUtils.util.Console; public class ConsoleTestApp { public static void main(String args[]) { // create the Console object Console c = new Console(); // display a welcome message c.println("Welcome to the Console Tester application"); c.println(); // int c.println("Int Test"); int i = c.getIntWithinRange("Enter an integer between -100 and 100: ", -101, 101); c.println(); I have a class called Console that is located in another package that I believe I have properly imported. here is the code I am stuck on in my console class. public int getIntWithinRange(String prompt, int min, int max) { int i = 0; boolean isValid = false; while (isValid == false) { System.out.println(prompt); if (sc.hasNextInt()) { //if user chooses menu option less than 1 the program will print an error message i = sc.nextInt(); if (i < min) { System.out.println("Error! Please enter an int greater than -100"); } else if (i > max) { System.out.println("Error! Please enter an int less than 100"); } else isValid = true; } else System.out.println("Error! Invalid number value"); sc.nextLine(); } // return the int return i; } when I run this I keep getting my last print which is an invalid number value. am I not importing the code from the main method in the other console properly?

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  • initializing a vector of custom class in c++

    - by Flamewires
    Hey basically Im trying to store a "solution" and create a vector of these. The problem I'm having is with initialization. Heres my class for reference class Solution { private: // boost::thread m_Thread; int itt_found; int dim; pfn_fitness f; double value; std::vector<double> x; public: Solution(size_t size, int funcNo) : itt_found(0), x(size, 0.0), value(0.0), dim(30), f(Eval_Functions[funcNo]) { for (int i = 1; i < (int) size; i++) { x[i] = ((double)rand()/((double)RAND_MAX))*maxs[funcNo]; } } Solution() : itt_found(0), x(31, 0.0), value(0.0), dim(30), f(Eval_Functions[1]) { for (int i = 1; i < 31; i++) { x[i] = ((double)rand()/((double)RAND_MAX))*maxs[1]; } } Solution operator= (Solution S) { x = S.GetX(); itt_found = S.GetIttFound(); dim = S.GetDim(); f = S.GetFunc(); value = S.GetValue(); return *this; } void start() { value = f (dim, x); } /* plus additional getter/setter methods*/ } Solution S(30, 1) or Solution(2, 5) work and initalizes everything, but I need X of these solution objects. std::vector<Solution> Parents(X) will create X solutions with the default constructor and i want to construct using the (int, int) constructor. Is there any easy(one liner?) way to do this? Or would i have to do something like: size_t numparents = 10; vector<Solution> Parents; Parents.reserve(numparents); for (int i = 0; i<(int)numparents; i++) { Solution S(31, 0); Parents.push_back(S); }

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  • c++ inline functions

    - by user69514
    i'm confused about how to do inline functions in C++.... lets say this function. how would it be turned to an inline function int maximum( int x, int y, int z ) { int max = x; if ( y > max ) max = y; if ( z > max ) max = z; return max; }

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  • Pointers to class fields

    - by newbie_cpp
    My task is as follows : Using pointers to class fields, create menu allowing selection of ice, that Person can buy in Ice shop. Buyer will be charged with waffel and ice costs. Selection of ice and charging buyers account must be shown in program. Here's my Person class : #include <iostream> using namespace std; class Iceshop { const double waffel_price = 1; public: } class Person { static int NUMBER; char* name; int age; const int number; double plus, minus; public: class Account { int number; double resources; public: Account(int number, double resources) : number(number), resources(resources) {} } Person(const char* n, int age) : name(strcpy(new char[strlen(n)+1],n)), number(++NUMBER), plus(0), minus(0), age(age) {} Person::~Person(){ cout << "Destroying resources" << endl; delete [] name; } friend void show(Person &p); int* take_age(){ return &age; } char* take_name(){ return name; } void init(char* n, int a) { name = n; age = a; } Person& remittance(double d) { plus += d; return *this; } Person& paycheck(double d) { minus += d; return *this; } Account* getAccount(); }; int Person:: Person::Account* Person::getAccount() { return new Account(number, plus - minus); } void Person::Account::remittance(double d){ resources = resources + d; } void Person::Account::paycheck(double d){ resources = resources - d; } void show(Person *p){ cout << "Name: " << p->take_name() << "," << "age: " << p->take_age() << endl; } int main(void) { Person *p = new Person; p->init("Mary", 25); show(p); p->remittance(100); system("PAUSE"); return 0; } How to start this task ? Where and in what form should I store menu options ?

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  • Why is a c++ reference considered safer than a pointer?

    - by anand.arumug
    When the c++ compiler generates very similar assembler code for a reference and pointer, why is using references preferred (and considered safer) compared to pointers? I did see Difference between pointer variable and reference variable in C++ which discusses the differences between them. EDIT-1: I was looking at the assembler code generated by g++ for this small program: int main(int argc, char* argv[]) { int a; int &ra = a; int *pa = &a; }

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  • "Use of uninitialised value" despite of memset

    - by Framester
    Hi there, I allocate a 2d array and use memset to fill it with zeros. #include<stdio.h> #include<string.h> #include<stdlib.h> void main() { int m=10; int n =10; int **array_2d; array_2d = (int**) malloc(m*sizeof(int*)); if(array_2d==NULL) { printf("\n Could not malloc 2d array \n"); exit(1); } for(int i=0;i<m;i++) { ((array_2d)[i])=malloc(n*sizeof(int)); memset(((array_2d)[i]),0,sizeof(n*sizeof(int))); } for(int i=0; i<10;i++){ for(int j=0; j<10;j++){ printf("(%i,%i)=",i,j); fflush(stdout); printf("%i ", array_2d[i][j]); } printf("\n"); } } Afterwards I use valgrind [1] to check for memory errors. I get following error: Conditional jump or move depends on uninitialised value(s) for line 24 (printf("%i ", array_2d[i][j]);). I always thought memset is the function to initialize arrays. How can I get rid off this error? Thanks! Valgrind output: ==3485== Memcheck, a memory error detector ==3485== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al. ==3485== Using Valgrind-3.5.0-Debian and LibVEX; rerun with -h for copyright info ==3485== Command: ./a.out ==3485== (0,0)=0 (0,1)===3485== Use of uninitialised value of size 4 ==3485== at 0x409E186: _itoa_word (_itoa.c:195) ==3485== by 0x40A1AD1: vfprintf (vfprintf.c:1613) ==3485== by 0x40A8FFF: printf (printf.c:35) ==3485== by 0x8048724: main (playing_with_valgrind.c:39) ==3485== ==3485== ==3485== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- ==3485== Conditional jump or move depends on uninitialised value(s) ==3485== at 0x409E18E: _itoa_word (_itoa.c:195) ==3485== by 0x40A1AD1: vfprintf (vfprintf.c:1613) ==3485== by 0x40A8FFF: printf (printf.c:35) ==3485== by 0x8048724: main (playing_with_valgrind.c:39) [1] valgrind --tool=memcheck --leak-check=yes --show-reachable=yes --num-callers=20 --track-fds=yes --db-attach=yes ./a.out [gcc-cmd] gcc -std=c99 -lm -Wall -g3 playing_with_valgrind.c

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  • Linked lists in Java - help with assignment

    - by user368241
    Representation of a string in linked lists In every intersection in the list there will be 3 fields : The letter itself. The number of times it appears consecutively. A pointer to the next intersection in the list. The following class CharNode represents a intersection in the list : public class CharNode { private char _data; private int _value; private charNode _next; public CharNode (char c, int val, charNode n) { _data = c; _value = val; _next = n; } public charNode getNext() { return _next; } public void setNext (charNode node) { _next = node; } public int getValue() { return _value; } public void setValue (int v) { value = v; } public char getData() { return _data; } public void setData (char c) { _data = c; } } The class StringList represents the whole list : public class StringList { private charNode _head; public StringList() { _head = null; } public StringList (CharNode node) { _head = node; } } Add methods to the class StringList according to the details : (I will add methods gradually according to my specific questions) (Pay attention, these are methods from the class String and we want to fulfill them by the representation of a string by a list as explained above) public int indexOf (int ch) - returns the index in the string it is operated on of the first appeareance of the char "ch". If the char "ch" doesn't appear in the string, returns -1. If the value of fromIndex isn't in the range, returns -1. Pay attention to all the possible error cases. Write what is the time complexity and space complexity of every method that you wrote. Make sure the methods you wrote are effective. It is NOT allowed to use ready classes of Java. It is NOT allowed to move to string and use string operations. Here is my try to write the method indexOf (int ch). Kindly assist me with fixing the bugs so I can move on. public int indexOf (int ch) { int count = 0; charNode pose = _head; if (pose == null ) { return -1; } for (pose = _head; pose!=null && pose.getNext()!='ch'; pose = pose.getNext()) { count++; } if (pose!=null) return count; else return -1; }

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  • Syntax error while copying an multidimensional array to another in C

    - by mantuko
    We are programming a ST269 microcontroller which has two IR distance sensors. To calibrate these sensors we made one table for each sensor with the distance we measured and the corresponding value we get from the ADC. Now we want to use one function to approximate the values in between. So we defined two two-dimensional arrays (one for each sensor) as global variables. In our function we then want to copy the one array we want to work with to a working array and approximate our values. So here's the code: ... unsigned int ir_werte_re[][] = { {8,553}, ... {83,133} }; unsigned int ir_werte_li[][] = { {8,566}, ... {83,147} }; ... unsigned int geradenaproximation(unsigned int messwert, unsigned int seite) { unsigned int working_array[16][16]; unsigned int i = 0; if (seite == 0) { for (i = 0; i < sizeof(working_array); i++) { working_array[i][0] = ir_werte_li[i][0]; i++; } } else { for (i = 0; i < sizeof(working_array); i++) { working_array[i][0] = ir_werte_re[i][0]; i++; } } i = 0; unsigned int y1 = 0; unsigned int x1 = 0; ... } This code is in a file called sensor.c. We didn't write anything about our global arrays in the sensor.h should we? The sensor.h of course is included in our main.c and there the function is called. We also tried to copy the arrays via memcpy(working_array, ir_werte_li, sizeof(working_array)); And in every way we do this we get a syntax error near unsigned in the line where we're declaring unsigned int y1 = 0; and I'm pretty sure that there is no syntax error in this line : ) The last time I spend coding in C is a few years away so I'm not sure if the way we try to do this is good. Perhaps we can solve this by using a pointer instead of really copying the array or something. So please help me out I'll appreciate your bits on this.

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  • creating an array of objects in c++

    - by tim22
    I'm trying to create an array of objects in c++. I'm creating a employee object, from my constructor in my company class here: employee obj(int tempIdNum, double tempBase, double tempSales, double tempRate); emp[tempcount]=obj; (this doesn't work?) Emp is the name of the array which is defined here, located in my company h file. Employee emp[4]; more code: Company::Company(string name, string fileName){ string str; int tempcount; int tempIdnum; double tempBase; double tempSales; double tempRate; double num; double arr[16]; this->name=name; //Commission temp; ifstream readFile; readFile.open("fileName"); int inc=0; while(tempcount<4){ for(int i=0+inc; i<4+inc; i++){ readFile>>num; arr[i-inc]=num; } tempIdnum=(int)(arr[0]); tempBase=arr[1]; tempSales=arr[2]; tempRate=arr[3]; Employee obj(int tempIdNum, double tempBase, double tempSales, double tempRate); emp[tempcount]=obj; inc+=4; tempcount++; } readFile.close(); } Here is some more from my h file #include <string> include "Commission.h" using namespace std; ifndef Company_H define Company_H class Company{ private: string name; //name of company Employee emp[4]; //array of payrool info about 4 commission employees int numEmp; //number of employees public: Company(); Company(string name, string fileName); ~Company(); string getName(); Commission getEmployee(int element); int getNumEmp(); }; endif enter code here Does not compile: 46 E:\exercise2\Company.cpp no match for 'operator=' in '((Company*)this)-Company::emp[tempcount] = obj'

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  • C newbie malloc question

    - by roufamatic
    Why doesn't this print 5? void writeValue(int* value) { value = malloc(sizeof(int)); *value = 5; } int main(int argc, char * argv) { int* value = NULL; writeValue(value); printf("value = %d\n", *value); // error trying to access 0x00000000 } and how can I modify this so it would work while still using a pointer as an argument to writeValue?

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  • Setting last N bits in an array

    - by Martin
    I'm sure this is fairly simple, however I have a major mental block on it, so I need a little help here! I have an array of 5 integers, the array is already filled with some data. I want to set the last N bits of the array to be random noise. [int][int][int][int][int] set last 40 bits [unchanged][unchanged][unchanged][24 bits of old data followed 8 bits of randomness][all random] This is largely language agnostic, but I'm working in C# so bonus points for answers in C#

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  • EBCDIC to ASCII conversion. Out of bound error. In C#.

    - by mekrizzy
    I tried creating a EBCDIC to ASCII convector in C# using this general conversion order(given below). Basically the program converted from ASCII to the equivalent integer and from there into EDCDIC using the order below. Now when I try compiling this in C# and try giving a EBCDIC string(got this from another file from another computer) it is showing 'Out of Bound' exception for some of the EBCDIC character. Why is this like this?? Is it about formating?? or C# ?? or windows? Extra: I tried just printing out all the ASCII and EBCDIC characters using a loop from 0..255 numbers but still its not showing many of the EBCDIC characters. Am I missing any standards? int[] eb2as = new int[256]{ 0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15, 16, 17, 18, 19,157,133, 8,135, 24, 25,146,143, 28, 29, 30, 31, 128,129,130,131,132, 10, 23, 27,136,137,138,139,140, 5, 6, 7, 144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26, 32,160,161,162,163,164,165,166,167,168, 91, 46, 60, 40, 43, 33, 38,169,170,171,172,173,174,175,176,177, 93, 36, 42, 41, 59, 94, 45, 47,178,179,180,181,182,183,184,185,124, 44, 37, 95, 62, 63, 186,187,188,189,190,191,192,193,194, 96, 58, 35, 64, 39, 61, 34, 195, 97, 98, 99,100,101,102,103,104,105,196,197,198,199,200,201, 202,106,107,108,109,110,111,112,113,114,203,204,205,206,207,208, 209,126,115,116,117,118,119,120,121,122,210,211,212,213,214,215, 216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231, 123, 65, 66, 67, 68, 69, 70, 71, 72, 73,232,233,234,235,236,237, 125, 74, 75, 76, 77, 78, 79, 80, 81, 82,238,239,240,241,242,243, 92,159, 83, 84, 85, 86, 87, 88, 89, 90,244,245,246,247,248,249, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,250,251,252,253,254,255 }; The whole code is as follows: public string convertFromEBCDICtoASCII(string inputEBCDICString, int initialPos, int endPos) { string inputSubString = inputEBCDICString.Substring(initialPos, endPos); int[] e2a = new int[256]{ 0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15, 16, 17, 18, 19,157,133, 8,135, 24, 25,146,143, 28, 29, 30, 31, 128,129,130,131,132, 10, 23, 27,136,137,138,139,140, 5, 6, 7, 144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26, 32,160,161,162,163,164,165,166,167,168, 91, 46, 60, 40, 43, 33, 38,169,170,171,172,173,174,175,176,177, 93, 36, 42, 41, 59, 94, 45, 47,178,179,180,181,182,183,184,185,124, 44, 37, 95, 62, 63, 186,187,188,189,190,191,192,193,194, 96, 58, 35, 64, 39, 61, 34, 195, 97, 98, 99,100,101,102,103,104,105,196,197,198,199,200,201, 202,106,107,108,109,110,111,112,113,114,203,204,205,206,207,208, 209,126,115,116,117,118,119,120,121,122,210,211,212,213,214,215, 216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231, 123, 65, 66, 67, 68, 69, 70, 71, 72, 73,232,233,234,235,236,237, 125, 74, 75, 76, 77, 78, 79, 80, 81, 82,238,239,240,241,242,243, 92,159, 83, 84, 85, 86, 87, 88, 89, 90,244,245,246,247,248,249, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,250,251,252,253,254,255 }; char chrItem = Convert.ToChar("0"); StringBuilder sb = new StringBuilder(); for (int i = 0; i < inputSubString.Length; i++) { try { chrItem = Convert.ToChar(inputSubString.Substring(i, 1)); sb.Append(Convert.ToChar(e2a[(int)chrItem])); sb.Append((int)chrItem); sb.Append((int)00); } catch (Exception ex) { Console.WriteLine("//" + ex.Message); return string.Empty; } } string result = sb.ToString(); sb = null; return result; }

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  • error: expected `;' before '{' token - What is the cause?

    - by melee
    Here is my implementation file: using namespace std; #include <iostream> #include <iomanip> #include <string> #include <stack> //line 5 #include "proj05.canvas.h" //----------------Constructor----------------// Canvas::Canvas() //line 10 { Title = ""; Nrow = 0; Ncol = 0; image[][100]; // line 15 position.r = 0; position.c = 0; } //-------------------Paint------------------// line 20 void Canvas::Paint(int R, int C, char Color) { cout << "Paint to be implemented" << endl; } The errors I'm getting are these: proj05.canvas.cpp: In function 'std::istream& operator>>(std::istream&, Canvas&)': proj05.canvas.cpp:11: error: expected `;' before '{' token proj05.canvas.cpp:22: error: a function-definition is not allowed here before '{' token proj05.canvas.cpp:24: error: expected `}' at end of input proj05.canvas.cpp:24: error: expected `}' at end of input These seem like simple syntax errors, but I am not sure what's wrong. Could someone decode these for me? I'd really appreciate it, thanks for your time! EDIT Here is the definition of Canvas in my .h file: #ifndef CANVAS_H #define CANVAS_H #include <iostream> #include <iomanip> #include <string> #include <stack> class Canvas { public: Canvas(); void Paint(int R, int C, char Color); const int Nrow; const int Ncol; string Title; int image[][100]; stack<int> path; struct PixelCoordinates { unsigned int r; unsigned int c; } position; }; #endif

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  • Making an efficient algorithm

    - by James P.
    Here's my recent submission for the FB programming contest (qualifying round only requires to upload program output so source code doesn't matter). The objective is to find two squares that add up to a given value. I've left it as it is as an example. It does the job but is too slow for my liking. Here's the points that are obviously eating up time: List of squares is being recalculated for each call of getNumOfDoubleSquares(). This could be precalculated or extended when needed. Both squares are being checked for when it is only necessary to check for one (complements). There might be a more efficient way than a double-nested loop to find pairs. Other suggestions? Besides this particular problem, what do you look for when optimizing an algorithm? public static int getNumOfDoubleSquares( Integer target ){ int num = 0; ArrayList<Integer> squares = new ArrayList<Integer>(); ArrayList<Integer> found = new ArrayList<Integer>(); int squareValue = 0; for( int j=0; squareValue<=target; j++ ){ squares.add(j, squareValue); squareValue = (int)Math.pow(j+1,2); } int squareSum = 0; System.out.println( "Target=" + target ); for( int i = 0; i < squares.size(); i++ ){ int square1 = squares.get(i); for( int j = 0; j < squares.size(); j++ ){ int square2 = squares.get(j); squareSum = square1 + square2; if( squareSum == target && !found.contains( square1 ) && !found.contains( square2 ) ){ found.add(square1); found.add(square2); System.out.println( "Found !" + square1 +"+"+ square2 +"="+ squareSum); num++; } } } return num; }

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  • Messing with the stack in assembly and c++

    - by user246100
    I want to do the following: I have a function that is not mine (it really doesn't matter here but just to say that I don't have control over it) and that I want to patch so that it calls a function of mine, preserving the arguments list (jumping is not an option). What I'm trying to do is, to put the stack pointer as it was before that function is called and then call mine (like going back and do again the same thing but with a different function). This doesn't work straight because the stack becomes messed up. I believe that when I do the call it replaces the return address. So, I did a step to preserve the return address saving it in a globally variable and it works but this is not ok because I want it to resist to recursitivy and you know what I mean. Anyway, i'm a newbie in assembly so that's why I'm here. Please, don't tell me about already made software to do this because I want to make things my way. Of course, this code has to be compiler and optimization independent. My code (If it is bigger than what is acceptable please tell me how to post it): // A function that is not mine but to which I have access and want to patch so that it calls a function of mine with its original arguments void real(int a,int b,int c,int d) { } // A function that I want to be called, receiving the original arguments void receiver(int a,int b,int c,int d) { printf("Arguments %d %d %d %d\n",a,b,c,d); } long helper; // A patch to apply in the "real" function and on which I will call "receiver" with the same arguments that "real" received. __declspec( naked ) void patch() { _asm { // This first two instructions save the return address in a global variable // If I don't save and restore, the program won't work correctly. // I want to do this without having to use a global variable mov eax, [ebp+4] mov helper,eax push ebp mov ebp, esp // Make that the stack becomes as it were before the real function was called add esp, 8 // Calls our receiver call receiver mov esp, ebp pop ebp // Restores the return address previously saved mov eax, helper mov [ebp+4],eax ret } } int _tmain(int argc, _TCHAR* argv[]) { FlushInstructionCache(GetCurrentProcess(),&real,5); DWORD oldProtection; VirtualProtect(&real,5,PAGE_EXECUTE_READWRITE,&oldProtection); // Patching the real function to go to my patch ((unsigned char*)real)[0] = 0xE9; *((long*)((long)(real) + sizeof(unsigned char))) = (char*)patch - (char*)real - 5; // calling real function (I'm just calling it with inline assembly because otherwise it seems to works as if it were un patched // that is strange but irrelevant for this _asm { push 666 push 1337 push 69 push 100 call real add esp, 16 } return 0; }

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  • Why wont extern link to a static variable?

    - by Jared P
    Why does extern int n not compile when n is declared (in a different file) static int n, but works when declared int n? (Both of these declarations were at file scope.) Basically, why is int n in file scope not the same as static int n in the same scope? Is it only in relation to extern? If so, what about extern am I missing?

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  • QTreeView incorrectly displays the SpinBox if item is checkable and when using QWindowsStyle

    - by Sharraz
    Hello, I'm having a problem with a QTreeView in my program: The SpinBox used to edit the double value of a checkable item is displayed incorrectly when using the Windows style. Only the up and down buttons of the SpinBox can be seen, but not any value. The following example code is able to reproduce the problem: #include <QtGui> class Model : public QAbstractItemModel { public: Model() : checked(false), number(0) {} Qt::ItemFlags flags(const QModelIndex & index) const { return Qt::ItemIsEnabled | Qt::ItemIsEditable | Qt::ItemIsSelectable | Qt::ItemIsUserCheckable; } QVariant data(const QModelIndex &index, int role) const { switch (role) { case Qt::DisplayRole: case Qt::EditRole: return QVariant(number); case Qt::CheckStateRole: return QVariant(checked ? Qt::Checked : Qt::Unchecked); } return QVariant(); } QVariant headerData(int section, Qt::Orientation orientation, int role) const { return QVariant(); } int rowCount(const QModelIndex &parent) const { return parent.isValid() ? 0 : 1; } int columnCount(const QModelIndex &parent) const { return parent.isValid() ? 0 : 1; } bool setData(const QModelIndex &index, const QVariant &value, int role) { switch (role) { case Qt::EditRole: number = value.toDouble(); emit dataChanged(index, index); return true; case Qt::CheckStateRole: checked = value.toInt(); emit dataChanged(index, index); return true; } return false; } QModelIndex index(int row, int column, const QModelIndex &parent) const { if (!row && !column && !parent.isValid()) return createIndex(0, 0); return QModelIndex(); } QModelIndex parent(const QModelIndex &child) const { return QModelIndex(); } private: bool checked; double number; }; int main(int argc, char *argv[]) { QApplication app(argc, argv); QApplication::setStyle(new QWindowsStyle()); QTreeView tree; tree.setModel(new Model()); tree.show(); return app.exec(); } The problems seems to have something to do with the checkbox. If Qt::ItemIsUserCheckable is removed, the SpinBox will be displayed correctly. If the number is replaced by a longer one like 0.01, it can be seen partially. Any idea how this problem can be solved? Do I use the checkbox correctly? Greets, Sharraz

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  • Confusion over C++ new operator and classes

    - by Nils
    Hi all I created a simple class in C++ which has a private dynamic array. In the constructor I initialize the array using new and in the destructor I free it using delete. When I instantiate the class using Class a = Class(..); it works as expected, however it seems I cannot instantiate it using the new operator (Like Class *a = new Class(..);), I always get a segmentation fault. What I don't understand is when I should use new to instantiate a class and when just call the constructor or should it be possible to instantiate a class either with new or by just calling the constructor. float** A = new float*[3]; for (int i=0; i<3; i++) { A[i] = new float[3]; } A[0][0] = 3; A[0][1] = 3; A[0][2] = 4; A[1][0] = 5; A[1][1] = 6; A[1][2] = 7; A[2][0] = 1; A[2][1] = 2; A[2][2] = 3; Matrix *M = new Matrix(A, 3, 3); delete[] A; delete M; Below the class definition.. class Matrix { private: int width; int height; int stride; float* elements; public: Matrix(float** a, int n, int m); ~Matrix(); }; Matrix::Matrix(float** a, int n, int m) { // n: num rows // m: elem per rows elements = new float[n*m]; for (int i=0; i<n; i++) { for (int j=0; j<m; j++) { elements[i*n + j] = a[n][m]; } } } Matrix::~Matrix() { delete[] elements; }

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  • Learning C, would appreciate input on why this solution works.

    - by Keifer
    This is literally the first thing I've ever written in C, so please feel free to point out all it's flaws. :) My issue, however is this: if I write the program the way I feel is cleanest, I get a broken program: #include <sys/queue.h> #include <stdlib.h> #include <stdio.h> #include <string.h> /* Removed prototypes and non related code for brevity */ int main() { char *cmd = NULL; unsigned int acct = 0; int amount = 0; int done = 0; while (done==0) { scanf ("%s %u %i", cmd, &acct, &amount); if (strcmp (cmd, "exit") == 0) done = 1; else if ((strcmp (cmd, "dep") == 0) || (strcmp (cmd, "deb") == 0)) debit (acct, amount); else if ((strcmp (cmd, "wd") == 0) || (strcmp (cmd, "cred") == 0)) credit (acct, amount); else if (strcmp (cmd, "fee") == 0) service_fee(acct, amount); else printf("Invalid input!\n"); } return(0); } void credit(unsigned int acct, int amount) { } void debit(unsigned int acct, int amount) { } void service_fee(unsigned int acct, int amount) { } As it stands, the above generates no errors at compile, but gives me a segfault when ran. I can fix this by changing the program to pass cmd by reference when calling scanf and strcmp. The segfault goes away and is replaced by warnings for each use of strcmp at compile time. Despite the warnings, the affected code works. warning: passing arg 1 of 'strcmp' from incompatible pointer type As an added bonus, modifying the scanf and strcmp calls allows the program to progress far enough to execute return(0), at which point the thing crashes with an Abort trap. If I swap out return(0) for exit(0) then everything works as expected. This leaves me with two questions: why was the original program wrong? How can I fix it better than I have? The bit about needing to use exit instead of return has me especially baffled.

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  • C++ boost function overloaded template

    - by aaa
    I cannot figure out why this segment gives unresolved overloaded function error (gcc version 4.3.4 (Debian 4.3.4-6)): #include <algorithm> #include <boost/function.hpp> int main { typedef boost::function2<const int&, const int&, const int&> max; max m(static_cast<max>(&std::max<int>)); } can you help me, thanks

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  • Mysql insert into 2 tables

    - by Spidfire
    I want to make a insert into 2 tables visits: visit_id int | card_id int registration: registration_id int | type enum('in','out') | timestamp int | visit_id int i want something like: INSERT INTO `visits` as v ,`registration` as v (v.`visit_id`,v.`card_id`,r.`registration_id`, r.`type`, r.`timestamp`, r.`visit_id`) VALUES (NULL, 12131141,NULL, UNIX_TIMESTAMP(), v.`visit_id`); I wonder if its possible

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  • java nested for() loop throws ArrayIndexOutOfBoundsException

    - by Mike
    I'm working through a JPanel exercise in a Java book. I'm tasked with creating a 5x4 grid using GridLayout. When I loop through the container to add panels and buttons, the first add() throws the OOB exception. What am I doing wrong? package mineField; import java.awt.*; import javax.swing.*; @SuppressWarnings("serial") public class MineField extends JFrame { private final int WIDTH = 250; private final int HEIGHT = 120; private final int MAX_ROWS = 5; private final int MAX_COLUMNS = 4; public MineField() { super("Minefield"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Container mineFieldGrid = getContentPane(); mineFieldGrid.setLayout(new GridLayout(MAX_ROWS, MAX_COLUMNS)); // loop through arrays, add panels, then add buttons to panels. for (int i = 0; i < MAX_ROWS; i++) { JPanel[] rows = new JPanel[i]; mineFieldGrid.add(rows[i], rows[i].getName()); rows[i].setBackground(Color.blue); for (int j = 0; j < MAX_COLUMNS; j++) { JButton[] buttons = new JButton[i]; rows[i].add(buttons[j], buttons[j].getName()); } } mineFieldGrid.setSize(WIDTH, HEIGHT); mineFieldGrid.setVisible(true); } public int setRandomBomb(Container con) { int bombID; bombID = (int) (Math.random() * con.getComponentCount()); return bombID; } /** * @param args */ public static void main(String[] args) { //int randomBomb; //JButton bombLocation; MineField minePanel = new MineField(); //minePanel[randomBomb] = minePanel.setRandomBomb(minePanel); } } I'm sure I'm over-engineering a simple nested for loop. Since I'm new to Java, please be kind. I'm sure I'll return the favor some day.

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