#include <stdio.h> 
#include <stdlib.h>

int main (int argc, char **argv )
{
    int x, y, w, q;

    if ( argc != 3 ) {
        printf("### Usage: %s <int> <int>\n", argv[0]);
        exit (EXIT_FAILURE);
    }
    if ( (x = atoi(argv[1])) <= 0 ) {
        printf("### Invalid argument [%s]\n", argv[1]);
        exit (EXIT_FAILURE);
    }
    if ( (y = atoi(argv[2])) <= 0 ) {
        printf("### Invalid argument [%s]\n", argv[2]);
        exit (EXIT_FAILURE);
    }
    if ( x < y ) {
        w = x;
        x = y;
        y = w;
    }

    for ( q = 1; q != 0 ; ) {
        q = x % y;
        w = x / y;
        printf("x=%d, y=%d, quotient=%d, residual=%d\n",
                x,       y,           w,           q);
        x = y;
        y = q;
    }
    printf("G.C.D of (%d,%d) is %d\n", 
               atoi(argv[1]), atoi(argv[2]), x );
    return EXIT_SUCCESS;
}