giaithua

#include<iostream>
using namespace std;

int giaithua(int n) {
	if (n == 1) {
		return 1;
	}
	else {
		return giaithua(n - 1)*n;
	}
}
void main() {
	int n;
	cout << "nhap n ";
	cin >> n;
	cout << giaithua(n);
	system("pause");
}