Задача 6,1

#include "stdafx.h"
#include <iostream>
using namespace std;


unsigned long long rec_fact(unsigned long long a)
{
    if (a == 0)
    {
        return 1;
    }
    else
    {
        return a*rec_fact(a - 1);
    }
}


int main()
{
    unsigned int a;
    setlocale(LC_ALL, "russian");
    system("color 0A");
    cin >> a;
    cout << rec_fact(a) << endl;
    system("pause");
    return 0;
}