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;
    long long fun(int);
    // write your code here......
    factorial=fun(n);

    cout << factorial << endl;
    
    return 0;
}
long long fun(int k )
    {if (k==1)            
    return 1;
    else
    return (k*fun(k-1));

    }