Question

I have this class with a foo method and the main method where I have a few variables and a print statement.

public static boolean foo(int x, boolean b) {
    if (x < 0) {
          return true;
    }
    return !b; 
}

Say I print the following:

foo (-3, c || !c)

I’m having trouble understanding what the || is supposed to do. I declared boolean c = false in main, but I don’t see how it can choose to input c (false) or !c (true). Also, side-question: the exclamation point in front of a boolean variable will just give the opposite right? i.e. if the input was false, and foo returns !b, it’d return true?

Answer 1

It’s a tautology so to speak, always true.

c || !c means: “c OR not c”. One of these is always true.