/* 
 * Tower of Hanoi
 * written by ASAKAWA Shinichi <asakawa@twcu.ac.jp>
 *
 * How to compile this source code
 *    gcc -o hanoi hanoi.c
 */
#include <stdio.h>
#include <stdlib.h>

int hanoi(int n, char x, char y, char z)
{
	if (n==1) {
		printf("move disk %d from %c to %c\n",n, x, y);
	} else {
		hanoi( n-1, x, z, y );
		printf("move disk %d from %c to %c\n",n, x, y);
		hanoi( n-1, z, y, x );
	}
	return EXIT_SUCCESS;
}

int main(int argc, char **argv)
{
	int disks = 3; /* default number of disks */

	if (argc == 2) {
		if ( (disks=atoi(argv[1]))<= 0 ) {
			fprintf(stderr, "Invalid argument %s\n", argv[1]);
			exit (EXIT_FAILURE);
		}
	}
	hanoi(disks, 'a', 'b', 'c');
	return EXIT_SUCCESS;
}