Nested Local Classes

It is possible to nest a class inside a local class. In this case, the nested class definition can appear outside the local-class body. However, the nested class must be defined in the same scope as that in which the local class is defined.

void foo()
{
    class Bar {
    public:
        // ...
        class Nested;     // declares class Nested
   };
   // definition of Nested
   class Bar::Nested {
       // ...
   };
}

As usual, when we define a member outside a class, we must indicate the scope of the name. Hence, we defined Bar::Nested, which says that Nested is a class defined in the scope of Bar.

A class nested in a local class is itself a local class, with all the attendant restrictions. All members of the nested class must be defined inside the body of the nested class itself.