条件运算符中的返回值

Question

I was trying to return value true or false depending upon the condition by using a conditional operator but I got an error. Here is my code,

bool isEmpty()
{
    int listSize = Node::size();
    listSize > 0 ? return (true) : return (false);
    return false;
}

And here is the error,

error C2107: illegal index, indirection not allowed

Now I am stuck here. I don't get the point.Logically I think it should be correct. Please guide me about it. Thanks

Answer 1

You can only have expressions* as the operands of the ternary conditional, not statements. The usual way to say this is:

return listSize > 0 ? true : false;

or even better,

return listSize > 0;

or even better,

bool isEmpty() { return Node::size() > 0; }

*) Since you tagged this as both C and C++, know that there is a subtle difference between the admissible expressions in the two languages.

Answer 2

The ternary operator ( ?: ) is not designed to be used like that. You have a syntax error.

Try this instead:

return (listSize > 0);

Answer 3

Unless you have a deeper reason for doing this that I am missing, you should just return (listSize > 0); .