Question

Circle Class

Write a Circle class that has the following member variables:
• radius: a double
• pi: a double initialized with the value 3.14159

The class should have the following member functions:

• Default Constructor. A default constructor that sets radius to 0.0.
• Constructor. Accepts the radius of the circle as an argument.
• setRadius. A mutator function for the radius variable.
• getRadius. An accessor function for the radius variable.
• getArea. Returns the area of the circle, which is calculated as area = pi * radius * radius
• getDiameter. Returns the diameter of the circle, which is calculated as diameter = radius * 2
• getCircumference. Returns the circumference of the circle, which is calculated as circumference = 2 * pi * radius

Write a program that demonstrates the Circle class by asking the user for the circle’s radius, creating a Circle object, and then reporting the circle’s area, diameter, and circumference.

SAMPLE RUN #0: ./circle_Non-Interactive

Interactive Session Standard Error (empty) Standard Output Hide Invisibles

Highlight: NoneStandard Input OnlyPrompts OnlyStandard Output w/o PromptsFull Standard OutputAllShow Highlighted Only

Calling·default·constructor:·The·circle's·radius·in·the·default·Circle·Object·is:·0↵
↵
Calling·setRadius(20)·to·change·radius·of·default:↵
The·circle's·radius·in·the·default·Circle·Object·is·Now:·20↵
↵
Creating·Circle·circle2(10):·↵
The·circle2's·radius·in·the·circle2·Object·is:·10↵
↵
The·circle2's·area·is·therefore:·314.159↵
The·circle2's·diameter·is·therefore:·20↵
The·circle2's·circumference·is·therefore:·62.8318↵

out put must be like sample run. HELP PLEASE

Answer 1

Java Program

import java.util.Scanner;   //importing Scanner utility class

public class Main   //Main class with main method for testing Circle class
{
        public static void main(String[] args) {
            Scanner sc = new Scanner(System.in);    
            
            System.out.print("Enter radius: "); //getting raidus input
            double radius = sc.nextDouble();    
            
            System.out.println("Calling·default·constructor:·The·circle's·radius·in·the·default·Circle·Object·is:·0\n");
            Circle circle = new Circle();   //creating a circle object by default constructor
            System.out.println("Calling·setRadius("+radius+")·to·change·radius·of·default:");
            circle.setRadius(radius);   //setting circle raidus to user inputted radius
            System.out.println("The·circle's·radius·in·the·default·Circle·Object·is·Now:·"+circle.radius+"\n");
            
            System.out.println("Creating·Circle·circle2(10):·");
            Circle circle2 = new Circle(10);    //creating circle2 by parametrized constructor 
            System.out.println("The·circle2's·radius·in·the·circle2·Object·is:·"+circle2.radius+"\n");
            
            System.out.println("The·circle2's·area·is·therefore:·"+circle2.getArea());
            System.out.println("The·circle2's·diameter·is·therefore:·"+circle2.getDiameter());
            System.out.println("The·circle2's·circumference·is·therefore:·"+circle2.getCircumference());
        }
}

class Circle    //Circle class definition
{
    public static double pi;    //class variable
    public double radius;       //object variable
    
    static      //static block executed only once when the class is loaded for the first time
    {
        pi = 3.14159;   //initializing static variables
    }
    Circle()    //default constructor called everytime an object is created
    {
        radius = 0.0;
    }
    Circle(double r)    //parametrized constructor
    {
        radius = r;
    }
    public void setRadius(double r) //setter method
    {
        radius = r;
    }
    public double getRadius()   //getter method
    {
        return radius;
    }
    public double getArea()     //computes and returns area of circle 
    {
        return pi*radius*radius;
    }
    public double getDiameter() //computes and returns circle diameter
    {
        return 2*radius;
    }
    public double getCircumference()    //computes and returns circle circumference
    {
        return 2*pi*radius;
    }
}

Program Screenshot

Output

Each and everything is explained clearly in the comment section of the code.

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