View Code of Problem 30

#include<iostream>
using namespace std;
int main(){
	int n;
	while(cin>>n){
		int a[n],sum=0;
		for(int i=0;i<n;i++){
			a[i]=i+1;
			sum+=a[i];
		}
		cout<<sum<<endl;		
		
	} 
	
	return 0;
}