Question

This is too basic I think, but how do both of these work?

return true;   // 1

and

return (true); // 2

Similar: sizeof, exit

My guess:

If return was a function, 1 would be
erroneous.

So, return should be a unary
operator that can also take in
brackets… pretty much like unary
minus: -5 and -(5), both are
okay.

Is that what it is – a unary operator?

Answer 1

return is a keyword that manipulates control flow. In that it’s similar to if, for etc. It can be used with or without an expression (return; returns from a void function). Of course, as with all expressions, extra parentheses are allowed. (So return (42); is similar to int i = (4*10+2);, in both cases the parentheses are redundant, but allowed.)

sizeof is a keyword that is an operator, similar to new, delete, +, ->, ::, etc.

std::exit() is an identifier that denotes a function of the C standard library (which never returns to the caller).