OOPS-lab-codes/ShapesDemo.java

import java.util.Scanner;

// -------- Interface for Circle --------
interface CircleOps {
    double circleArea();
    double circlePerimeter();
}

// -------- Interface for Rectangle --------
interface RectangleOps {
    double rectangleArea();
    double rectanglePerimeter();
}

// -------- Interface inheriting both --------
interface ShapeOps extends CircleOps, RectangleOps {
    void displaySummary();
}

// -------- Base class --------
class ShapeBase {

    double radius;
    double length;
    double breadth;
}

// -------- Implementing class --------
class ShapeCalculator extends ShapeBase implements ShapeOps {

    ShapeCalculator(double radius, double length, double breadth) {
        this.radius = radius;
        this.length = length;
        this.breadth = breadth;
    }

    // Circle operations
    public double circleArea() {
        return Math.PI * radius * radius;
    }

    public double circlePerimeter() {
        return 2 * Math.PI * radius;
    }

    // Rectangle operations
    public double rectangleArea() {
        return length * breadth;
    }

    public double rectanglePerimeter() {
        return 2 * (length + breadth);
    }

    // Summary method
    public void displaySummary() {
        System.out.println("\n--- Shape Summary ---");
        System.out.println("Circle Area: " + circleArea());
        System.out.println("Circle Perimeter: " + circlePerimeter());
        System.out.println("Rectangle Area: " + rectangleArea());
        System.out.println("Rectangle Perimeter: " + rectanglePerimeter());
    }
}

// -------- Demo class --------
public class ShapesDemo {

    // Method accepting CircleOps
    static void circleOperations(CircleOps c) {
        System.out.println("\nCircle Area: " + c.circleArea());
        System.out.println("Circle Perimeter: " + c.circlePerimeter());
    }

    // Method accepting RectangleOps
    static void rectangleOperations(RectangleOps r) {
        System.out.println("\nRectangle Area: " + r.rectangleArea());
        System.out.println("Rectangle Perimeter: " + r.rectanglePerimeter());
    }

    // Method accepting ShapeOps
    static void shapeOperations(ShapeOps s) {
        s.displaySummary();
    }

    // -------- Main method --------
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter radius of circle: ");
        double radius = sc.nextDouble();

        System.out.print("Enter length of rectangle: ");
        double length = sc.nextDouble();

        System.out.print("Enter breadth of rectangle: ");
        double breadth = sc.nextDouble();

        ShapeCalculator shape = new ShapeCalculator(radius, length, breadth);

        // Polymorphism using interface references
        circleOperations(shape);
        rectangleOperations(shape);
        shapeOperations(shape);

        sc.close();
    }
}