Added Java lab programs

ShapesDemo.java

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+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();
+    }
+}