AbstractClassProgram.java

/*Write a java program to create an abstract class named 
Shape that contains two integers and an empty method named 
print Area (). Provide three classes named Rectangle, Triangle 
and Circle such that each one of the classes extends the class 
Shape. Each one of the classes contains only the method print 
Area () that prints the area of the given shape.*/

import java.util.*;

abstract class Shape {
    int length, breadth, radius;

	Scanner input = new Scanner(System.in);

	abstract void printArea();

}

class Rectangle extends Shape {
	void printArea() {
		System.out.println("** Finding the Area of Rectangle **");
		System.out.print("Enter length and breadth: ");
		length = input.nextInt();
		breadth = input.nextInt();
		System.out.println("The area of Rectangle is: " + length * breadth);
	}
}

class Triangle extends Shape {
	void printArea() {
		System.out.println("\n** Finding the Area of Triangle **");
		System.out.print("Enter Base And Height: ");
		length = input.nextInt();
		breadth = input.nextInt();
		System.out.println("The area of Triangle is: " + (length * breadth) / 2);
	}
}

class Cricle extends Shape {
	void printArea() {
		System.out.println("\n** Finding the Area of Cricle **");
		System.out.print("Enter Radius: ");
		radius = input.nextInt();
		System.out.println("The area of Cricle is: " + 3.14f * radius * radius);
	}
}

public class AbstractClassProgram {
	public static void main(String[] args) {
		Rectangle rec = new Rectangle();
		rec.printArea();

		Triangle tri = new Triangle();
		tri.printArea();
		
		Cricle cri = new Cricle();
		cri.printArea();
	}
}