1 / 1Write a program in Java to create two instances of a Window class with references w1 and w2.
Here's an example program in Java that creates two instances of a Window class with references w1 and w2:
javaCopy codepublic class Window {
private int width;
private int height;
public Window(int width, int height) {
this.width = width;
this.height = height;
}
public void display() {
System.out.println("Window size: " + width + "x" + height);
}
}
public class Main {
public static void main(String[] args) {
Window w1 = new Window(640, 480);
Window w2 = new Window(800, 600);
w1.display();
w2.display();
}
}
In this program, the Window class has two instance variables width and height, and a constructor that initializes these variables with the passed values. The display() method simply prints the window size to the console.
The Main class contains the main() method which creates two instances of the Window class with references w1 and w2. It then calls the display() method on each window to print its size to the console.
1 / 1Now add in w1 two instances c11 of the class Circle with refernces c11 and c12 and two instances of the class Rectangle with refernces r11 and r12.
Sure! Here's the updated program in Java that creates two instances of the Circle class with references c11 and c12, and two instances of the Rectangle class with references r11 and r12, and adds them to the Window instance w1:
javaCopy codepublic class Circle {
private int radius;
public Circle(int radius) {
this.radius = radius;
}
public void display() {
System.out.println("Circle radius: " + radius);
}
}
public class Rectangle {
private int width;
private int height;
public Rectangle(int width, int height) {
this.width = width;
this.height = height;
}
public void display() {
System.out.println("Rectangle size: " + width + "x" + height);
}
}
public class Window {
private int width;
private int height;
private Circle c11, c12;
private Rectangle r11, r12;
public Window(int width, int height) {
this.width = width;
this.height = height;
this.c11 = new Circle(50);
this.c12 = new Circle(30);
this.r11 = new Rectangle(100, 50);
this.r12 = new Rectangle(80, 60);
}
public void display() {
System.out.println("Window size: " + width + "x" + height);
c11.display();
c12.display();
r11.display();
r12.display();
}
}
public class Main {
public static void main(String[] args) {
Window w1 = new Window(640, 480);
Window w2 = new Window(800, 600);
w1.display();
w2.display();
}
}
In this program, the Circle and Rectangle classes have been added, each with their own constructor that initializes their instance variables. The display() method of each class simply prints their respective size to the console.
The Window class now has four instance variables, c11, c12, r11, and r12, which are instances of the Circle and Rectangle classes. These instances are created and initialized in the constructor of the Window class.
In the display() method of the Window class, we print out the window size along with the sizes of the Circle and Rectangle instances contained in the window.
The Main class remains the same as before, creating two instances of the Window class and calling their display() methods.
1 / 1Write a program WindowsApp in Java that creates two instances of a Window class with references w1 and w2.
Sure! Here's an example program in Java that creates a WindowsApp class which creates two instances of a Window class with references w1 and w2:
javaCopy codepublic class Window {
private int width;
private int height;
public Window(int width, int height) {
this.width = width;
this.height = height;
}
public void display() {
System.out.println("Window size: " + width + "x" + height);
}
}
public class WindowsApp {
public static void main(String[] args) {
Window w1 = new Window(640, 480);
Window w2 = new Window(800, 600);
w1.display();
1 / 1Circle instances should not be created by Window instances but by the WindowsApp
Sure, here's the updated program with the Circle instances created by the WindowsApp class instead of the Window class:
javaCopy codepublic class Circle {
private int radius;
public Circle(int radius) {
this.radius = radius;
}
public void display() {
System.out.println("Circle radius: " + radius);
}
}
public class Rectangle {
private int width;
private int height;
public Rectangle(int width, int height) {
this.width = width;
this.height = height;
}
public void display() {
System.out.println("Rectangle size: " + width + "x" + height);
}
}
public class Window {
private int width;
private int height;
private Circle c1, c2;
private Rectangle r1, r2;
public Window(int width, int height, Circle c1, Circle c2, Rectangle r1, Rectangle r2) {
this.width = width;
this.height = height;
this.c1 = c1;
this.c2 = c2;
this.r1 = r1;
this.r2 = r2;
}
public void display() {
System.out.println("Window size: " + width + "x" + height);
c1.display();
c2.display();
r1.display();
r2.display();
}
}
public class WindowsApp {
public static void main(String[] args) {
Circle c1 = new Circle(50);
Circle c2 = new Circle(30);
Rectangle r1 = new Rectangle(100, 50);
Rectangle r2 = new Rectangle(80, 60);
Window w1 = new Window(640, 480, c1, c2, r1, r2);
Window w2 = new Window(800, 600, c1, c2, r1, r2);
w1.display();
w2.display();
}
}
In this updated program, the Circle and Rectangle classes remain the same. The Window class now takes Circle and Rectangle instances as parameters to its constructor, instead of creating them itself.
The WindowsApp class now creates the Circle and Rectangle instances and passes them to the Window constructors for w1 and w2. This allows the Circle instances to be shared between the two windows, while still allowing different instances of Rectangle to be used for each window.
The WindowsApp class creates the instances of Window with references w1 and w2, and calls their display() methods to print their sizes to the console.
1 / 1modify the Window class to keep track of Circle instances by using a java array
Sure! Here's an updated Window class that keeps track of Circle instances using a Java array:
javaCopy codepublic class Circle {
private int radius;
public Circle(int radius) {
this.radius = radius;
}
public void display() {
System.out.println("Circle radius: " + radius);
}
}
public class Rectangle {
private int width;
private int height;
public Rectangle(int width, int height) {
this.width = width;
this.height = height;
}
public void display() {
System.out.println("Rectangle size: " + width + "x" + height);
}
}
public class Window {
private int width;
private int height;
private Circle[] circles;
private Rectangle[] rectangles;
public Window(int width, int height, int numCircles, int numRectangles) {
this.width = width;
this.height = height;
this.circles = new Circle[numCircles];
this.rectangles = new Rectangle[numRectangles];
}
public void addCircle(int index, Circle circle) {
circles[index] = circle;
}
public void addRectangle(int index, Rectangle rectangle) {
rectangles[index] = rectangle;
}
public void display() {
System.out.println("Window size: " + width + "x" + height);
for (Circle circle : circles) {
if (circle != null) {
circle.display();
}
}
for (Rectangle rectangle : rectangles) {
if (rectangle != null) {
rectangle.display();
}
}
}
}
public class WindowsApp {
public static void main(String[] args) {
Circle c1 = new Circle(50);
Circle c2 = new Circle(30);
Rectangle r1 = new Rectangle(100, 50);
Rectangle r2 = new Rectangle(80, 60);
Window w1 = new Window(640, 480, 2, 2);
w1.addCircle(0, c1);
w1.addCircle(1, c2);
w1.addRectangle(0, r1);
w1.addRectangle(1, r2);
Window w2 = new Window(800, 600, 2, 2);
w2.addCircle(0, c1);
w2.addCircle(1, c2);
w2.addRectangle(0, r1);
w2.addRectangle(1, r2);
w1.display();
w2.display();
}
}
In this updated program, the Window class has been modified to use a Java array to keep track of Circle instances, rather than using individual instance variables. The constructor takes two additional parameters, numCircles and numRectangles, which specify the number of Circle and Rectangle instances that the Window object will contain.
The addCircle() and addRectangle() methods have been added to allow instances of Circle and Rectangle to be added to the array in the Window object. These methods take an index parameter which specifies the position in the array where the instance should be added.
The display() method has been modified to loop through the circles and rectangles arrays and display each non-null instance. The WindowsApp class has been modified to create instances of Window with references w1 and w2, and to add the instances of Circle and Rectangle to each Window instance using the addCircle() and addRectangle() methods.
1 / 1Add now a method draw in Circle
Sure, here's an updated version of the Circle class with a draw() method added:
javaCopy codepublic class Circle {
private int radius;
public Circle(int radius) {
this.radius = radius;
}
public void display() {
System.out.println("Circle radius: " + radius);
}
public void draw() {
System.out.println("Drawing circle with radius " + radius);
}
}
The draw() method simply prints a message to indicate that a circle is being drawn, along with its radius. You can use this method to draw circles in your program, as follows:
javaCopy codeCircle c1 = new Circle(50);
c1.draw(); // will print "Drawing circle with radius 50"