函数嵌套的练习

#include<iostream>
using namespace std;
//函数嵌套的练习:
double f1(int m, int n);
long f2(int x);
long f3(int x);
double f1(int m, int n)
{
	return f2(m)/f2(n);
}

long f2(int x)
{
	int sum = 0;
	for (int i = 0; i < x; i++)
	{
		sum += f3(i);
	}
	return sum;
}

long f3(int x)
{
	int ret = 1;
	for (int i = 1; i <= x; i++)
	{
		ret *= i;
	}
	return ret;
}

int main()
{
	int m = 0;
	int n = 0;
	cout << "请输入m与n的值:" << endl;
	cin >> m >> n;
	cout << "f(m,n)=" << f1(m, n) << endl;
	return 0;
}