Tower of Hanoi problem

Hanoi.c

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

/*
 * Tower of Hanoi problem
 *
 * T(n)=2T(n-1)+1 => T(n)=2^n-1
 */

static int steps=0;
 
void print_step(char src, char dst)
{
	steps++;
	printf("Move top from %c to %c\n",src, dst);
}

void hanoi(int n, char src, char mid, char dst)
{
	if(n==1){
		print_step(src, dst);
	}else{
		hanoi(n-1, src, dst, mid);
		print_step(src, dst);
		hanoi(n-1, mid, src, dst);
	}
}

int main(int argc, char** argv)
{
	if(argc!=2){
		printf("Usage: %s n\n",argv[0]);
		exit(-1);
	}

	hanoi(atoi(argv[1]),'A','B','C');
	printf("%d steps\n",steps);
    return 0;
}