C++ SDL program terminates immediately

Question

I've been following LazyFoo's tutorial for a while. But I haven't been able to get this to initialize a week a go. I went back to it recently, after error checking, I found it that the window initializes properly, but the images won't load. What is the reason for it?

 #include "SDL/SDL.h"
    #include <string>

    //setting screen info
    const int SCH=640;
    const int SCW=480;
    const int BBP=32;
    const char* name = "TEHGAEM";

    // sprite height and width
    const int SPH=45;
    const int SPW=45;

//initilize event
    SDL_Event event;

//loading surfaces for screen, sprite, and temp sprite   
    SDL_Surface *screen=NULL;
    SDL_Surface *sprite=NULL;
    SDL_Surface *temp = NULL;
//making class for movable objects
    class Player
    {
        private:
        int x,y;
        int xVel,yVel;
        public:
        Player();
        void show();
        void move();
        void handle_input();
    };

//initializing variables
    Player::Player()
    {
        x=0;
        y=0;
        xVel=0;
        yVel=0;
    }
 //intended to show player picture
    void Player::show()
    {
         SDL_Rect pos;
        pos.x=x;
        pos.y=y;
        SDL_BlitSurface(sprite, NULL, screen, &pos);
        SDL_UpdateRects(screen, 1, &pos);
    }
  //setting input
    void Player::handle_input()
    {
        if (event.type ==SDL_KEYDOWN)
        {
            switch (event.key.keysym.sym)
            {
                case SDLK_UP: yVel -= SPH /2; break;
                case SDLK_DOWN: yVel += SPH /2; break;
                case SDLK_LEFT: xVel -=SPW /2; break;
                case SDLK_RIGHT: xVel +=SPW /2; break;
            }
        }
        if (event.type == SDL_KEYUP)
        {
            switch(event.key.keysym.sym)
            {
                case SDLK_UP: yVel += SPH /2; break;
                case SDLK_DOWN: yVel -= SPH /2; break;
                case SDLK_LEFT: xVel +=SPW /2; break;
                case SDLK_RIGHT: xVel -=SPW /2; break;
            }
        }
    }

    void Player::move()
    {
        x=+xVel;
        y=+yVel;
        if (x >= SCW)
        {
            x-10;
        }
        if (y >= SCH)
        {
            y-10;
        }
    }

//initializing program

    bool init()
    {
        if (SDL_Init(SDL_INIT_EVERYTHING)==-1)
        {
            return false;
        }
        screen = SDL_SetVideoMode(SCH,SCW,BBP, SDL_SWSURFACE);
        if (screen == NULL)
        {
            return false;
        }
        SDL_WM_SetCaption(name, NULL);
        return true;
    }

//loading images
    bool somethings()
    {
        temp = SDL_LoadBMP("sprite.bmp");
        if (temp == NULL)
        {
            return false;
        }
        sprite = SDL_DisplayFormat (temp);
        if (sprite ==NULL)
        {
            return false;
        }
        SDL_FreeSurface(temp);

        return true;
    }

    //clean up function
    void clean()
    {
        SDL_FreeSurface(sprite);
        SDL_Quit();
    }




    int main(int argc, char* args[])
    {
        Player P1;
        bool quit;
        if (init() == false)
        {
            return 1;
        }

        if (somethings() ==false)
        {
            return 1;
        }

        while (quit ==false)
        {
            while (SDL_PollEvent(&event))
            {
                P1.handle_input();
                if (event.type == SDL_QUIT)
                {
                    quit == true;
                }
            }
            if (SDL_Flip(screen) ==-1)
            {
                return 1;
            }
            P1.move();
            P1.show();
        }
        clean();
        return 0;
    }

Answer 1

This isn't completely related to your problem but the varible bool quit; isn't defined as true or false before the main while( quit == false ) { ... } loop. This could produce undefined while loop behavior.

int main(int argc, char* args[])
    {
        Player P1;
        bool quit = false; // CHANGE THIS AND SEE WHAT HAPPENS
        if (init() == false)
        {
            return 1;
        }

        if (somethings() ==false)
        {
            return 1;
        }

        while (quit ==false)
        {
            while (SDL_PollEvent(&event))
            {
                P1.handle_input();
                if (event.type == SDL_QUIT)
                {
                    quit == true;
                }
            }
            if (SDL_Flip(screen) ==-1)
            {
                return 1;
            }
            P1.move();
            P1.show();
        }
        clean();
        return 0;
    }

About the images not loading, step through your program with a debugger and watch your somethings() function and follow the variables temp and sprite.

Answer 2

Make sure your "sprite.bmp" file is located in the running directory of this program. I tested it and it works for me.

Also this has no effect:

        if (x >= SCW)
        {
            x-10;
        }
        if (y >= SCH)
        {
            y-10;
        }

You probably wanted to say x -= 10; and y -= 10; .

This makes your 'player' jump back to the original position immediately:

if (event.type == SDL_KEYUP)
        {
            switch(event.key.keysym.sym)
            {
                case SDLK_UP: yVel += SPH /2; break;
                case SDLK_DOWN: yVel -= SPH /2; break;
                case SDLK_LEFT: xVel +=SPW /2; break;
                case SDLK_RIGHT: xVel -=SPW /2; break;
            }
        }

You probably only need to handle SDL_KEYDOWN event.

Hope that helps.

Answer 3

There are big chances that you aren't loading the bitmap. But anything that you are trying to print on the screen and wasn't loaded can terminate the app.