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

The warning means it's possible to go through your method without returning any explicit value. With your code:

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

if side != left and side != right, then you don't return anything. A common way of fixing this problem is to assume, for example, if not "left" then always assume "right":

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