高手们,一道C++编程小题!!!高分!!!

#include<iostream>
using namespace std;
int fun(int n);
int main()
{
int n = 0;
cout<<"请输入一个正整数：";
cin>>n;
if(n < 0)
{
cout<<"请输入正整数"<<endl;
return 0;
}
cout<<n<<"的阶乘是"<<fun(n)<<endl;
return 0;
}
int fun(int n)
{
int f = 0;
if(n == 1)
f = 1;
else if(n > 1)
f = fun(n - 1) * n;
return f;
}

#include<iostream>
using namespace std;
int f(int n)
{
if(n>0)return n*f(n-1);
else return 1;
}
int main()
{
int n;
cout<<"please input n:"<<endl;
cin>>n;
cout<<f(n)<<endl;
return 0;
}