Allegro program triggers breakpoint? - sprite

Question

So I'm learning about sprite programming and we're using allegro. When I run one of the sample programs I get the message: rotatesprite.exe has triggered a breakpoint. This was in visual studio. I can't get allegro to work outside of visual studio
sample program:
#include <allegro.h>
#define WHITE makecol(255,255,255)
int main(void)
{
int x, y;
float angle = 0;
BITMAP *tank;
//initialize program
allegro_init();
install_keyboard();
set_color_depth(32);
set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);
textout_ex(screen,font,"Rotate: LEFT / RIGHT arrow keys",
0,0,WHITE,0);
//load tank sprite
tank = load_bitmap("C:\Users\Jason\Desktop\module7\tank.bmp", NULL);
//calculate center of screen
//x = SCREEN_W/2 - tank->w/2;
//y = SCREEN_H/2 - tank->h/2;
x=SCREEN_W/2;
y=SCREEN_H/2;
//draw tank at starting location
rotate_sprite(screen, tank, x, y, 0);
//main loop
while(!key[KEY_ESC])
{
//wait for keypress
if (keypressed())
{
//left arrow rotates left
if (key[KEY_LEFT])
{
angle -= 0.1;
if (angle < 0) angle = 256;
rotate_sprite(screen, tank, x, y, itofix(angle));
}
//right arrow rotates right
if (key[KEY_RIGHT])
{
angle += 0.1;
if (angle > 256) angle = 0;
rotate_sprite(screen, tank, x, y, itofix(angle));
}
//display angle
textprintf_ex(screen, font, 0, 10, WHITE, 0,
"Angle = %f", angle);
}
}
allegro_exit();
return 0;
}
END_OF_MAIN()
the program triggering the breakpoint is: crt0msg.c off of the disk.
snippet of code:
#ifdef _DEBUG
/*
* Report error.
*
* If _CRT_ERROR has _CRTDBG_REPORT_WNDW on, and user chooses
* "Retry", call the debugger.
*
* Otherwise, continue execution.
*
*/
if (rterrnum!=_RT_CRNL&&rterrnum!=_RT_BANNER&&rterrnum!=_RT_CRT_NOTINIT)
{
if (1 == _CrtDbgReport(_CRT_ERROR, NULL, 0, NULL,rterrs[tblindx].rterrtxt))
_CrtDbgBreak();
}
#endif /* _DEBUG */

Answer 1

tank = load_bitmap("C:\Users\Jason\Desktop\module7\tank.bmp", NULL);
Your compiler should be warning you about that string since it contains invalid escaped characters. You should use double back slashes or single forward slashes:
tank = load_bitmap("C:\\Users\\Jason\\Desktop\\module7\\tank.bmp", NULL);
// or
tank = load_bitmap("C:/Users/Jason/Desktop/module7/tank.bmp", NULL);
The latter format is recommended because it is cross platform. (Minus the whole bit about hard coding an absolute path.)
Finally, you really need to check return codes:
if (!tank) {
// gracefully report error and exit
}
Otherwise the program will crash somewhere else and it will be harder to debug.