CS12, Lab 2

Lab Cycle of April 19--23

Topics:

· Friend functions

· Overloading the insertion operator (<<) for output

· Static class members and static member functions.

In this lab you will be modifying the Dice class from lab 1 to Enhance its usability.

You will be adding a friend function to overload the << operator. This will perform a function similar to the method roll(), but instead of returning the result of the roll, it will print it out. In addition, you will add a static class member that will keep track of the number of Dice objects in existence in the program.

To do:

· Copy the files dice.h and dice.cpp, which contain the Dice class.

· Add an overloaded operator<< as a friend function of the class. The function should be defined in dice.h and implemented in dice.cpp. Do not forget to update my_rolls in the function. The overloaded operator should take an ostream reference object as a parameter and return a reference to an ostream.

· Add a static data member num_dice which will contain the number of Dice objects in existence

· Initialize num_dice properly in dice.cpp

· Add appropriate code to the constructor and destructor that will update num_dice.

· Add a static method numDice() which will return the number of Dice objects in the program.

· Write a main() that will test both enhancements you made to the Dice class. It should declare a few Dice objects, check how many are in existence using the numDice() method, and also print out the result of rolling one of the dice using cout << my_d; instead of my_d.roll(); (assume my_d is a declared Dice object).

Extra credit:

· The main program creates objects and uses numDice() to count them. It does not check whether num_dice is appropriately decreased when an object ceases to exist, because the objects you declared are only destructed at the end of main(), as the last thing done by the program. How would you test if num_dice is decreased correctly? Design a short program to test this and write it.