More Exceptional C++

Chapter 33. Simulating Nested Functions

Difficulty: 5

C++ has nested classes, but not nested functions. When might nested functions be useful, and can they be simulated in C++?

1. What is a nested class? Why can it be useful?

2. What is a local class? Why can it be useful?

3. C++ does not support nested functions. That is, we cannot write something like

   // Example 33-3
   //
   int f( int i )
   {
     int j = i*2;
   
     int g( int k )  // not valid C++
     {
       return j+k;
     }
   
     j += 4;
   
     return g( 3 );
   }
   

   Demonstrate how it is possible to achieve the same effect in standard C++, and show how to generalize the solution.

Solution

Recap: Nested and Local Classes

C++ provides many useful tools for ...