Question

Write a Circle class that has the following member variables:

• radius as a double
• PI as a double initialized with 3.14159

The class should have the following member functions:

• Default constructor Sets the radius as 0.0 and pi as 3.14159
• Constructor Accepts the radius of the circles as an argument
• setRadius A mutator
• getRadius An accessor
• getArea Returns the area of the circle
• getDiameter Returns the diameter of the circle
• getCircumference Returns the circumference of the circle

Write a program that demonstrates the Circle class by asking the user for the radius, creating a Circle class object and then uses the object to test the class.

Sample output:

Enter the circle's radius: 55.5

Radius: 55.5

Area : 9676.88

Diameter: 111

Circumference: 348.716

Answer 1

class Circle {

    private double Radius;
    private final double PI = 3.14159;

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

    public Circle() {
        Radius = 0.0;
    }

    public double getRadius() {
        return Radius;
    }

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

    public double getArea() {
        return PI * Radius * Radius;
    }

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

    public double getCircumference() {
        return 2 * PI * Radius;
    }
}

class ClassDemo {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter the circle's radius: ");
        double radius = in.nextDouble();
        Circle circle = new Circle(radius);
        System.out.println("Radius: " + circle.getRadius());
        System.out.println("Area: " + circle.getArea());
        System.out.println("Diameter: " + circle.getDiameter());
        System.out.println("Circumference: " + circle.getCircumference());
    }
}