Using Constructor
// Interface declaration
interface Shape {
double area(); // Abstract method to calculate area
}
// Circle class implementing Shape interface
class Circle implements Shape {
double radius;
// Constructor to initialize radius
Circle(double radius) {
this.radius = radius;
}
// Implementation of area method
public double area() {
return Math.PI * radius * radius;
}
}
// Rectangle class implementing Shape interface
class Rectangle implements Shape {
double length, width;
// Constructor to initialize length and width
Rectangle(double length, double width) {
this.length = length;
this.width = width;
}
// Implementation of area method
public double area() {
return length * width;
}
}
// Main class to demonstrate functionality
public class ShapeAreaDemo {
public static void main(String[] args) {
Shape circle = new Circle(5);
Shape rectangle = new Rectangle(4, 6);
// Calculating and printing areas
System.out.println("Circle Area: " + circle.area()); System.out.println("Rectangle Area: " + rectangle.area());
}
}
// Using Setter Methods
import java.io.*;
interface Shape1 {
double area();
}
// Circle class implementing Shape1 interface
class Circle implements Shape1
{
double radius;
// Method to set the radius
public void setRadius(double r) {
radius = r;
}
// Implementation of area method
public double area() {
return Math.PI * radius * radius;
}
}
// Rectangle class implementing Shape1 interface
class Rectangle implements Shape1 {
double length, width;
// Method to set length and width
public void setDimensions(double l, double w) {
length = l;
width = w;
}
// Implementation of area method
public double area() {
return length * width;
}
}
public class ShapeAreaDemo1 {
public static void main(String[] args) {
Circle circle = new Circle();
circle.setRadius(5);
// Creating a Rectangle object and setting dimensions
Rectangle rectangle = new Rectangle();
rectangle.setDimensions(4, 6);
System.out.println("Circle Area: " + circle.area());
System.out.println("Rectangle Area: " + rectangle.area());
}
}
