/* Bitmap Graphics Program */

#include <graphics.h>
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include <limits.h>

#define VGA256 0x13
#define TEXT 0x03

void setMode (int mode)
{
asm { mov ax, mode
int 0x10 }
}

unsigned char far *videoBuffer = (unsigned char far *) 0xA0000000L;

void putPixel (int x, int y, int color)
{
videoBuffer [((y<<8) + (y<<6)) + x] = (unsigned char) color;
}

int main ()
{
clrscr ();
int gdriver = DETECT, gmode, errorcode;
initgraph (&gdriver, &gmode, "g:\\bgi");
errorcode = graphresult ();

if (errorcode != grOk)
{
printf ("Graphics error: %s \n", grapherrormsg (errorcode));
printf ("Press Anykey to halt: ");
getch ();
exit (1);
}

/* "graphics main prorgam lines" go here */

int color, j;
setMode (VGA256);

for (color=0; color<256; color++)
{
for (j=0; j<200; j++)
{
putPixel (color, j, color);
}
}

getch ();
setMode (TEXT);
closegraph ();

return 0;
}

Download Bitmapgr.cpp