#include <iostream>

using namespace std;

int main()
{
    setlocale(LC_ALL,"Hun");

    cout.setf(ios::fixed);
    cout.precision(0);

    cout << "Faktoriális számítás!" << endl << endl;

    int n;
    int f;

    string tmp;
    char ch = 'I';
    do{
        cout << endl << "n = " ;
        cin >> n; getline(cin,tmp);
        if(cin.fail() || n<0){
            cout << "Természetes szám kell!" << endl;
            cin.clear(); getline(cin,tmp);
            continue;
        }

        f = 1;
        for(int i = 2; i<=n; ++i){
            f = f * i;
        }

        cout << "n!= " << f << endl;

        cout << "Folytatod? (I/N)";
        cin >> ch; getline(cin,tmp);
    }while( !('n'==ch || 'N'==ch) );

    return 0;
}