Pointers to Functions bubble sort Program example 5 in C programming language

 Pointers to Functions bubble Program Example 5 : 

 /*---------------------- bubble5.c ---------------------------*/

/* Program bubble_5.c from PTRTUT10.HTM    6/13/97 */

#include <stdio.h>
#include <string.h>

long arr[10] = { 3,6,1,2,3,8,4,1,7,2};

void bubble(void *p, size_t width, int N);
int compare(void *m, void *n);

int main(void)
{
    int i;
    putchar('\n');

    for (i = 0; i < 10; i++)
    {
        printf("%d ", arr[i]);
    }
    bubble(arr, sizeof(long), 10);
    putchar('\n');

    for (i = 0; i < 10; i++)
    {
        printf("%ld ", arr[i]);
    }

    return 0;
}

void bubble(void *p, size_t width, int N)
{
    int i, j;
    unsigned char buf[4];
    unsigned char *bp = p;
 for (i = N-1; i >= 0; i--)
    {
        for (j = 1; j <= i; j++)
        {
            if (compare((void *)(bp + width*(j-1)),
                        (void *)(bp + j*width)))  /* 1 */
            {
/*              t = p[j-1];   */
                memcpy(buf, bp + width*(j-1), width);
/*              p[j-1] = p[j];   */
                memcpy(bp + width*(j-1), bp + j*width , width);
/*              p[j] = t;   */
                memcpy(bp + j*width, buf, width);
            }
        }
    }
}

int compare(void *m, void *n)
{
    long *m1, *n1;
    m1 = (long *)m;
    n1 = (long *)n;
    return (*m1 > *n1);
}

/*--------------------- end of bubble5.c ---------------------*/