#include <stdio.h>

#define X_SIZE 40 /* size of array in the X direction */
#define Y_SIZE 60 /* size of the array in Y direction */
/*
 * We use X_SIZE/8 since we pack 8 bits per byte
 */
char graphics[X_SIZE / 8][Y_SIZE];   /* the graphics data */

#define SET_BIT(x,y) graphics[(x)/8][y] |= (0x80 >>((x)%8))

main()
{
    int   loc;        /* current location we are setting */
    void  print_graphics(void); /* print the data */

    for (loc = 0; loc < X_SIZE; loc++)
        SET_BIT(loc, loc);

    print_graphics();
    return (0);
}
/********************************************************
 * print_graphics -- print the graphics bit array       *
 *              as a set of X and .'s.                  *
 ********************************************************/
void print_graphics(void)
{
    int x;     /* current x BYTE */
    int y;     /* current y location */
    int bit;   /* bit we are testing in the current byte */

    for (y = 0; y < Y_SIZE; y++) {
        /* Loop for each byte in the array */
        for (x = 0; x < X_SIZE / 8; x++) {
            /* Handle each bit */
            for (bit = 0x80; bit > 0; bit = (bit >> 1)) {
                if ((graphics[x][y] & bit) != 0)
                    (void) printf("X");
                else
                    (void) printf(".");
            }
        }
        (void) printf("\n");
    }
}