Do not define a default clause for enum in switch statement! Say in future, if another fruit type is added to the enum, default clause shall cause the C++ compiler not to warn you that you have not handled the case for the new fruit.

enum class Fruit
{
    Apple,
    Orange
};

Fruit fruit = ...;
switch(fruit)
{
    case Fruit::Apple: ... 
        break;
    case Fruit::Orange: ... 
        break;
    default: ... // <-- Do not ever define a default clause for enum!
}

As a point of interest, first item under Bad Coding Practices is CWE-478: Missing Default Case in Switch Statement advises programmers to put default clause in their switch statement.