randomise(strings, n)
char *strings[];
int n;
{
    int i;
    int v;
    char *t;

     
    for (i = 0; i < 1000 ; i++) {
	v = rand() % 1000 ;
	t = strings[v];
	strings[v] = strings[i];
	strings[i] = t;
    }
}

check_order(sort_type, strings, n)
char *sort_type;
char *strings[];
int n;
{
    int i;

    for (i = 0; i < n; i++) {
	if (atoi(strings[i]) != i) {
	    printf("%s sort failed - exiting\n", sort_type);
	    exit(1);
	}
    }
}

qs_string_compare(a, b)
char *a,*b;
{
    return strcmp(*(char **)a, *(char **)b);
}

main()
{
    char *strings[1000 ], *strings_copy[1000 ];
    char buffer[1000 *(6 +1)];
    char *p;
    int i;

    p = buffer;
    for (i = 0; i < 1000 ; i++) {
	sprintf(p, "%06d" , i);
	strings[i] = p;
	p += 6 +1;
    }
    randomise(strings, 1000 );

    memcpy(strings_copy, strings, sizeof(strings));
    qsort(strings_copy, 1000 , sizeof(char *), qs_string_compare);
    check_order("Quick", strings_copy, 1000 );
}