//  factorial.c++ computes factorial, takes
//                command line argument
//  $ g++ -Wall factorial.c++ -o factorial
#include <iostream>
using namespace std;
#include <cstdlib>
int main(int count, char *vects[]) {
    int n, i, fact = 1 ;
 
    if(count < 2) {
      cerr << "Missing 2nd argument\n" ;
      return 0 ;
    }
    n = atoi(vects[1]) ;
    for(i=1; i<=n; ++i) fact *=i ;
    cout << n << "! = " << fact << endl;
    return 0 ;
}