What does “warning: not all control paths return a value” mean? (C++)

Question

The exact warning I get is

warning C4715: \'hand::show\' : not all control paths return a value

and hand::show is

std::ostr         


        

Answer 1

To get rid of the warning, replace the second if with an else:

std::ostream& hand::show(std::ostream& os) const
{
    if(side == left)
    {
        return os<