Page 179 - CTS - CSA TP - Volume 2
P. 179
COMPUTER SOFTWARE APPLICATION - CITS
class Rectangle extends Shape {
private double length;
private double width;
// Constructor
public Rectangle(double length, double width) {
this.length = length;
this.width = width;
}
// Implementation of abstract method
@Override
public double calculateArea() {
return length * width;
}
}
// Main class
public class AbstractClassExample {
public static void main(String[] args) {
// Create instances of concrete classes
Circle circle = new Circle(5.0);
Rectangle rectangle = new Rectangle(4.0, 6.0);
// Call abstract and concrete methods
circle.displayArea(); // Calls abstract method implementation in Circle
rectangle.displayArea(); // Calls abstract method implementation in Rectangle
}
}
Explanation:
1 Abstract Class (Shape):
• Declares an abstract method calculateArea() without implementation.
• Defines a concrete method displayArea() that calls the abstract method.
2 Concrete Classes (Circle and Rectangle):
• Extend the abstract class Shape.
• Provide implementations for the abstract method calculateArea().
3 Main Class (AbstractClassExample):
• Creates instances of concrete classes.
• Demonstrates calling abstract and concrete methods.
164
CITS : IT & ITES - Computer Software Application - Exercise 110
