1001.cpp

杭州电子科技大学ACM-OJ系统的部分代码

#include<iostream>
using namespace std;
unsigned long sum(unsigned long n)
{ 
	unsigned long i;
    i=(n*(n+1))/2;
	return i;
} 
int main()
{
	unsigned long n;
	while(cin>>n)
	{
		cout<<sum(n)<<endl;
		cout<<endl;
	}
	return 0;
}