Need for code explanation

[owCRE3v7]

Hello!

I got a code, for avoidance of any signs input, despite "int" characters.

Please, explain me step by step what exactly is happening here?

  while (!(cin >> x) || (cin.peek() != '\n') || x <= 0)
            //
        {
            cin.clear();
            //
            while (cin.get() != '\n');
            //
            cout << "Error. Not a Natural number. Try one more time" << endl;

[lastchance]

It attempted to read an int with cin >> x.

If it failed (the ! part) ...
... or if there was something left on the line before the new line ...
... or if x was non-positive ...

then it:
- cleared the stream of any errors;
- kept inputting characters up to and including the new line from the enter key;
- told you in no uncertain terms that you’d boobed.


It seems a bit obfuscatory, to be honest. But I expect I’ve written worse.

[seeplus]

while (cin.get() != '\n');

is often replaced with:

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

whatever rocks your boat....

Note that || is a short-circuit logical operator. The terms are only evaluated left to right until one term evalutes to true or they have all been evaluated in which case the result is false.