题解 | #计算一个数的阶乘#

#include <iostream>
using namespace std;

int main() {
    
    int n;
    cin >> n;
    long long factorial = 1;
    
    // write your code here......
    if(n>=1 && n<=20){
        for (int i=1;i<=n;i++){
            factorial*=i;
        }
        
    }

    cout << factorial << endl;
    
    return 0;
}