#include

using namespace std;

int main()

{

int n;

cout << "请输入一个正整数：";

cin >> n;

int i = 1;

int sum = 0;

while(i <= n)

{

sum += i;

i++;

}

cout << "1到" << n << "的累加和为：" << sum << endl;

return 0;

}