Answer:
Here is the Balloon class:
public class Balloon { //class name
private double volume; //private member variable of type double of class Balloon to store the volume
public Balloon() { //constructor of Balloon
volume = 0; } //constructs an empty balloon by setting value of volume to 0 initially
void addAir(double amount) { //method addAir that takes double type variable amount as parameter and adds given amount of air
volume = volume + amount; } //adds amount to volume
double getVolume() { //accessor method to get volume
return volume; } //returns the current volume
double getSurfaceArea() { //accessor method to get current surface area
return volume * 3 / this.getRadius(); } //computes and returns the surface area
double getRadius() { //accessor method to get the current radius
return Math.pow(volume / ((4 * Math.PI) / 3), 1.0/3); } } //formula to compute the radius
Explanation:
Here is the BalloonTester class
public class BalloonTester { //class name
public static void main(String[] args) { //start of main method
Balloon balloon = new Balloon(); //creates an object of Balloon class
balloon.addAir(100); //calls addAir method using object balloon and passes value of 100 to it
System.out.println("Volume "+balloon.getVolume()); //displays the value of volume by getting value of volume by calling getVolume method using the balloon object
System.out.println("Surface area "+balloon.getSurfaceArea()); //displays the surface area by calling getSurfaceArea method using the balloon object
System.out.println("Radius "+balloon.getRadius()); //displays the value of radius by calling getRadius method using the balloon object
balloon.addAir(100); //adds another 100 cm3 of air using addAir method
System.out.println("Volume "+balloon.getVolume()); //displays the value of volume by getting value of volume by calling getVolume method using the balloon object
System.out.println("Surface area "+balloon.getSurfaceArea()); //displays the surface area by calling getSurfaceArea method using the balloon object
System.out.println("Radius "+balloon.getRadius()); } } //displays the value of radius by calling getRadius method using the balloon object
//The screenshot of the output is attached.
