#include <iostream.h>

int factorial(int);

void main(void) {
    int number;

    cout << "Please enter a positive integer: ";
    cin >> number;
    if (number < 0)
        cout << "That is not a positive integer.\n";
    else
        cout << number << " factorial is: " << factorial(number) << endl;
}

int factorial(int number) {
    int temp;

    if(number <= 1) return 1;

    temp = number * factorial(number - 1);
    return temp;
}