break

#include <iostream>

using namespace std;

int main()
{

//累加键盘输入的数据
double x, sum = 0.0;
while (1)
{
	cout << "x=";
	cin >> x;
	if (x <= 0)
		break;
	sum += x;
}
cout << "sum=" << sum << endl;
return 0;

}