C++: Infinite loop with a simple menu selection

问题

The script I am working on is over a page long, so I am going to link it (one simple file):
http://pastebin.com/7BVHmQGp

I apologize for that. My problem is I get into an infinite loop in my code, for example after I select 1 or 2 for encrypting/unencrypting it lets me enter the word, and when I next enter the "shift" for the cipher it runs an infinite loop of the menu.

I had tried for so many hours to debug this, I thought it was a problem with cin, for example when you enter an invalid choice it just throws an infinite loop/

What seems to cause the infininte loops?

回答1:

I think you should be ignoring the newline character instead of a space

I tried with the following and it works on VS2010

    cin.ignore(1, '\n');
    getline(cin, input);

回答2:

Try cin.clear, I believe you are constantly reading your initial input character.

    cin >> selection;
    cin.clear(); 

回答3:

This page should explain all you need to know.

来源：https://stackoverflow.com/questions/4342068/c-infinite-loop-with-a-simple-menu-selection