Exceptional C++: 47 Engineering Puzzles, Programming Problems, and Solutions

Chapter 44. Casts

Difficulty: 6

How well do you know C++'s casts? Using them well can greatly improve the reliability of your code.

The new-style casts in standard C++ offer more power and safety than the old-style (C-style) casts. How well do you know them? The rest of this problem uses the following classes and global variables:

class  A { public: virtual ~A(); /*...*/ }; 
A::~A() { }

class B : private virtual A  { /*...*/ };

class C : public  A          { /*...*/ };

class D : public B, public C { /*...*/ };

A a1; B b1; C c1; D d1;
const A  a2;
const A& ra1 = a1;
const A& ra2 = a2;
char c;

This Item presents four questions.

1. Which of the following new-style casts are not equivalent to a C-style cast?

   const_cast 
   dynamic_cast
   reinterpret_cast
   static_cast
   

2. For each ...