填写缺少的部分以打印两个数字的总和（由用户输入）：
int x, y;
int sum;
cout << "Type a number: ";
@(3) >> @(1);
cout << "Type another number: ";
@(3) >> @(1);
sum = x + y;
cout << "Sum is: " << @(3);
int x, y;
int sum;
cout << "Type a number: ";
cin >> x;
cout << "Type another number: ";
cin >> y;
sum = x + y;
cout << "Sum is: " << sum;