#include<bits/stdc++.h>
using namespace std;
int f(int n)
{
if(n==1)
return 1;
else
return f(n-1)+n;
}
int main()
{
int a;
cin>>a;
cout<<f(a)<<endl;
return 0;
}
标签：std,return,int,5.16,打卡,main From： https://www.cnblogs.com/Sunyiran/p/17405841.html