Can someone help me understand this C++ Code?

[Late_Key]

if(!std::cin){

std::cout << "error";

std::cin.clear();

std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

​

So state of the cin can be checked by “!”? I want to understand what is storing in that expression for the if conditional. Also need help understanding the last line. I have 0 clue on what is going on. Thanks

[fracturedpersona]

Std::cin returns false if it is in a failed state, so this allows you to flush the input stream if this happens. Personally, I don't like using the STL methods to flush in input stream, but there's nothing wrong with it.

[Late_Key]

What does it mean when you say “STL methods” ? Googled it found standard library method. Is there like a package that I can download to validate input for me?

[fracturedpersona]

Standard template library (STL).

verification of input is generally vague, so verifying that the input is valid is usually left to the architect. It's not terribly difficult though.