Sams Teach Yourself C in 21 Days

Object-Oriented Programming Languages 637

BD1

LISTINGB1.2 cube.cpp. C++ OOP in action

1: // A C++ program with square and cube classes

2: #include <iostream.h>

3:

4: // Simple square class

5: class square {

6: public:

7: square();

8: square(int);

9: int length;

10: long area();

11: int draw();

12: };

13:

14: //simple cube class inheriting from the square class

15: class cube: public square {

16: public:

17: cube( int );

18: long area();

19: };

20:

21: //constructor for square

22: square::square()

23: {

24: length = 4;

25: }

26:

27: //overloaded constructor for square

28: square::square( int init_length )

29: {

30: length = init_length;

31: }

32:

33: //square class’ area function

34: long square::area( void )

35: {

36: return((long) length * length);

37: }

FIGUREB1.3

A cube inherits parts

of a square.

(x, y)

length

square

Area of square = length * length

(x, y)

cube

Area of cube = Area of square * length

length

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