如何在c++中检查输入是否为数字

I want to create a program that takes in integer input from the user and then terminates when the user doesn't enter anything at all (ie, just presses enter). However, I'm having trouble validating the input (making sure that the user is inputting integers, not strings. atoi() won't work, since the integer inputs can be more than one digit.I want to create a program that takes in intege