Question

Write an ADT named circle in java containing the following.

1. Include data:
   • radius (double)
2. Include methods:
   • A no-argument constructor
   • A constructor that sets the data to passed values
   • Getters and setters for each piece of data
   • getArea (Math.PI * radius * radius … try using a Math method here)
   • getDiameter (radius * 2)
   • getCircumference (2 * Math.PI * radius)
   • A toString( ) method to display the object data
3. Include Javadoc comments for the class and every method, and generate the Javadoc/API
4. Create a separate Java application to “unit test” this class by creating 2 objects: create one using the default constructor, and create the other one using radius values you get as input from the user.  Make sure you call every method at least one time.

Answer 1

import java.util.Scanner;

class Circle {
    private double radius;

    public Circle() {
        radius = 10;
    }

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

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

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

    public double getDiameter() {
        return 2 * radius;
    }

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

    @Override
    public String toString() {
        return "Circle{" +
                "radius=" + radius +
                ", area=" + getArea() +
                ", diameter=" + getDiameter() +
                ", circumference=" + getCircumference() +
                '}';
    }
}

public class Main {
    public static void main(String[] args) {
        Circle c1 = new Circle();
        Circle c2;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the radius: ");
        double radius = sc.nextInt();
        c2 = new Circle(radius);

        System.out.println("Circle 1: " + c1);
        System.out.println("Circle 2: " + c2);
    }
}