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

Chapter 10. Writing Exception-Safe Code—Part 3

Difficulty: 9½

Are you getting the hang of exception safety? Well, then, it must be time to throw you a curve ball. So get ready, and don't swing too soon.

Now for the final piece of Cargill's original Stack template.

template <class T> class Stack 
{
public:
  Stack();
  ~Stack();
  Stack(const Stack&);
  Stack& operator=(const Stack&);
size_t Count() const;
void  Push(const T&);
T    Pop(); // if empty, throws exception
private:
  T*     v_;      // ptr to a memory area big
  size_t vsize_;  //  enough for 'vsize_' T's
  size_t vused_;  // # of T's actually in use
};

Write the final three Stack functions: Count(), Push(), and Pop(). Remember, be exception-safe and exception-neutral!

Solution

Count()

The easiest of all Stack's members ...