c++编写一个求n!的函数，并调用s=1/1!+1/2!+1/3!+……+1/n!和sum=n!/(n－m)!×m!)+(n＞m)

以下是C++编写一个求n!的函数，并调用s=1/1!+1/2!+1/3!+……+1/n!和sum=n!/(n-m)!×m!)+(n＞m)的例子：

#include<iostream>
using namespace std;

// 求n的阶乘
int factorial(int n){
    if(n == 0 || n == 1){
        return 1;
    }
    else{
        return n * factorial(n-1);
    }
}

int main(){
    int n = 5, m = 2;
    double s = 0, sum = 0;
    for(int i = 1; i <= n; i++){
        s += 1.0 / factorial(i);
    }
    sum = factorial(n) / (factorial(n-m) * factorial(m));
    cout << "s = " << s << endl;
    cout << "sum = " << sum << endl;
    return 0;
}