Java Interface: Shape with the getArea() method, implement the Shape interface

Java Interface: Exercise-1 with Solution

Write a Java program to create an interface Shape with the getArea() method. Create three classes Rectangle, Circle, and Triangle that implement the Shape interface. Implement the getArea() method for each of the three classes.

Sample Solution:

Java Code:

// Shape.java
// Interface Shape

public interface Shape {
    double getArea();
}

// Rectangle.java
// Class Rectangle that implements the Shape interface

public class Rectangle implements Shape {
    private double length;
    private double width;

    public Rectangle(double length, double width) {
        this.length = length;
        this.width = width;
    }

    @Override
    public double getArea() {
        return length * width;
    }
}

// Circle.java
// Class Circle that implements the Shape interface

public class Circle implements Shape {
    private double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    @Override
    public double getArea() {
        return Math.PI * radius * radius;
    }
}

// Triangle.java
// Class Triangle that implements the Shape interface

public class Triangle implements Shape {
    private double base;
    private double height;

    public Triangle(double base, double height) {
        this.base = base;
        this.height = height;
    }

    @Override
    public double getArea() {
        return 0.5 * base * height;
    }
} 

// Main.java
// Main class that creates objects of Rectangle, Circle, and Triangle

public class Main {
    public static void main(String[] args) {
        //length=10,width=12
		Rectangle rectangle = new Rectangle(10, 12);
		//radius=3
        Circle circle = new Circle(3);
        //base=4,height=6
		Triangle triangle = new Triangle(4, 6);

        System.out.println("Area of the Rectangle: " + rectangle.getArea());
        System.out.println("Area of the Circle: " + circle.getArea());
        System.out.println("Area of the Triangle: " + triangle.getArea());
    }
}

Sample Output:

Area of the Rectangle: 120.0
Area of the Circle: 28.274333882308138
Area of the Triangle: 12.0 

Flowchart of Interface Shape:

Flowchart of Class Rectangle:

Flowchart of Class Circle:

Flowchart of Class Triangle:

Flowchart of Main Class:

Java Code Editor:

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