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

int main ()
{
    const char * haystack = "Giant Haystack";
    int pos = 'a';
    const char * location;

    location = haystack;
    while (1) {
	location = strchr (location, pos);
	/* strchr returns NULL (0) if the character is not found. */
	if (! location) {
	    puts ("End of string.");
	    break;
	}
	printf ("Found %c at position %d\n", pos, location - haystack);
	/* Skip over this character and start looking again. */
	location++;
    }
    /* Now go right to left. */
    location = haystack;
    location = strrchr (location, pos);
    /* strrchr returns NULL (0) if the character is not found. */
    if (! location) {
	printf ("%c was not found.", pos);
    }
    else {
	printf ("Found rightmost %c at position %d\n",
		pos, location - haystack);
    }
    return 0;
}