#include <stdio.h>

int reverse(char string[], int i);

/* reverses command line argument */
int main(int argc, char *argv[])
{
    if (argc < 2)
        return 1;
    printf("length :   %d\n", reverse(argv[1], 0));
    printf("reversed : %s\n", argv[1]);
    return 0;
}

/* reverse: reverses string from index i, returns length 
 * recursive implementation */
int reverse(char s[], int i)
{
    if (s[i] == '\0') { /* base case */
        return 0; 
    }
    int j = reverse(s, i+1);
    if (j > i) { /* swap elements */
        char c;
        c = s[i], s[i] = s[j], s[j] = c;
    }
    return j+1;
}