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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: Interface Shape

Flowchart of Class Rectangle:

Flowchart: Class Rectangle that implements the Shape interface

Flowchart of Class Circle:

Flowchart: Class Circle that implements the Shape interface

Flowchart of Class Triangle:

Flowchart: Class Triangle that implements the Shape interface

Flowchart of Main Class:

Flowchart: Main class that creates objects of Rectangle, Circle, and Triangle

Java Code Editor:

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Java: Tips of the Day

How do I remove repeated elements from ArrayList?

If you don't want duplicates in a Collection, you should consider why you're using a Collection that allows duplicates. The easiest way to remove repeated elements is to add the contents to a Set (which will not allow duplicates) and then add the Set back to the ArrayList:

Set<String> set = new HashSet<>(yourList);
yourList.clear();
yourList.addAll(set);

Of course, this destroys the ordering of the elements in the ArrayList.

Ref: https://bit.ly/3bYIjNC

 





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