Page 469 - Computer science 868 Class 12
P. 469
Program 8 An abstract base class Side is defined as follows:
Class name : Side
Data Members
int s : To store side of a square
Member Methods
Side(int ss) : Constructor to initialise data member
abstract void area() : Abstract method
void display() : To display side of the square
A derived class Area is defined to find and display the area of a square. The details of the
class is given below.
Class name : Area
Data Member
int a : To store area of a square
Member Methods
Area(int ss) : Constructor to initialise data member of both base and
derived classes
void area() : To calculate area of square
void display() : To display side of the square and area respectively
Also define the main method to create object of the derived class to implement the above.
1 abstract class Side //abstract base class
2 { int s;
3 Side(int ss) // constructor
4 { s=ss;}
5 abstract void area(); // abstract method
6 void display() // non abstract method
7 { System.out.println("Side of the square="+s+" cm");}
8 }
9 class Area extends Side
10 { int a;
11 Area(int ss)
12 { super(ss); //invoking super class constructor
13 a=0;}
14 void area() // implementaion of abstract method of base class
15 { a=s*s;}
16 void display()
17 { super.display();
18 System.out.println("Area ="+a+" cm^2");
19 }
20 public static void main(int sz)
467
Inheritance, Interfaces and Polymorphism 467

