题解 | #函数实现计算一个数的阶乘#

#include <iostream>
using namespace std;

long long factorial(int n);

int main() {

    int n;
    cin >> n;

    cout << factorial(n) << endl;

    return 0;
}

long long factorial(int n) {

    // write your code here......
    long long sum = 1;
    if (n == 0)
        sum = 1;
    else
    {
        for (int i=1; i<=n; i++){
            sum *= i;    
    }
    }
    return sum;
}