Exceptional C++ Style 40 New Engineering Puzzles, Programming Problems, and Solutions

Chapter 31. Amok Code

Difficulty: 4

Sometimes life hands you some debugging situations that seem just plain deeply weird. Try this one on for size, and see if you can reason about possible causes for the problem.

Guru Question

1. One programmer has written the following code:

   //--- file biology.h ---
   //
   
   // … appropriate includes and other stuff …
   class Animal {
   public:
    // Functions that operate on this object:
    //
    virtual int Eat (int) { /*…*/ }
    virtual int Excrete (int) { /*…*/ }
    virtual int Sleep (int) { /*…*/ }
    virtual int Wake (int) { /*…*/ }
   
    // Apparently for animals that were once married, and
    // sometimes dislike their ex-spouses, we provide:
    //
    int EatEx (Animal* a) { /*…*/ }
    int ExcreteEx (Animal* a) { /*…*/ }
    int SleepEx (Animal* a) { /*…*/ ...