Practice 1 Sum Function.cpp

#include<iostream>
using namespace std;
int sum(int n){
	if(n==0){
		return 0;
	}
	int prevsum=sum(n-1);
	return n+prevsum;
}
int main(){
	int n;
	cin>>n;
	cout<<sum(n)<<endl;
	return 0;
}