Programming Principles 1
1.2 THE GAME OF LIFE
Exercises 1.2
Determine by hand calculation what will happen to each of the configurations shown in Figure 1.1 over
the course of five generations. [Suggestion: Set up the Life configuration on a checkerboard. Use one color of checkers for living cells in the current generation and a second color to mark those that will be born or die in the next generation.]
Answer
(a)
Figure remains stable.
(b)
(c)
(d)
Figure is stable.
1
2 Chapter 1 _ Programming Principles
(e)
(f)
Figure repeats itself.
(g)
(h)
(i)
Figure repeats itself.
(j)
(k)
(l)
Figure repeats itself.
Section 1.3 _ Programming Style 3
1.3 PROGRAMMING STYLE
Exercises 1.3
E1. What classes would you define in implementing the following projects? What methods would your classes
possess?
(a) A program to store telephone numbers.
Answer The program could use classes called Phone_book and Person. The methods for a
Phone_book
object would include look_up_name, add_person, remove_person. The methods for a Person object would include Look_up_number. Additional methods to initialize and print objects of
both classes would also be useful.
(b) A program to play Monopoly.
Answer The program could use classes called Game_board, Property, Bank, Player, and Dice. In addition
to initialization and printing methods for all classes, the following methods would be useful. The class Game_board needs methods next_card and operate_jail. The class Property needs methods change_owner, look_up_owner, rent, build, mortgage, and unmortgage. The class Bank needs methods pay and collect. The class Player needs methods roll_dice, move_location, buy_property and pay_rent. The class Dice needs a method roll.
(c) A program to play tic-tac-toe.
Answer The program could use classes called Game_board and Square. The classes need initialization and printing methods. The class Game_board would also need methods make_move and
is_game_over. The class Square would need methods is_occupied, occupied_by, and occupy. (d) A program to model the build up of queues of cars waiting at a busy intersection with a traffic light. Answer The program could use classes Car, Traffic_light, and Queue. The classes would all need initialization
and printing methods. The class Traffic_light would need additional methods change_status
and status. The class Queue would need additional methods add_car and remove_car.
E2. Rewrite the following class definition, which is supposed to model a deck of playing cards, so that it
conforms to our principles of style.
class a { // a deck of cards
int X; thing Y1[52]; /* X is the location of the top card in the deck. Y1 lists the cards. */ public:
a( );
void Shuffle( ); // Shuffle randomly arranges the cards.
thing d( ); // deals the top card off the deck
}
;
Answer
class Card_deck {
Card deck[52];
int top_card;
public:
Card_deck( );
void Shuffle( );
Card deal( );
