> For the complete documentation index, see [llms.txt](https://www.computersciencea.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.computersciencea.com/older/session-20.md). # Session 20 ## Source Code ```java import java.util.*; public class Week20 { public static void main(String[] args) { String myName = ""; // add your name System.out.println("Week 20" + " - " + myName); // Menu System.out.println("Menu"); System.out.println("E1 - Example 1"); System.out.println("Q - Quit"); // setup Scanner Scanner in = new Scanner(System.in); System.out.print("Choice: "); String choice = in.nextLine(); // switch choices switch (choice) { case "E1": System.out.println("Example 1"); example1(); break; case "E2": System.out.println("Example 2"); example2(); break; case "E3": System.out.println("Example 3"); example3(); break; case "E4": System.out.println("Example 4"); example4(); break; case "Q": System.out.println("Quitting..!"); break; } } // example1 method public static void example1() { // Create Objects // Create an array of Felines // populate the array with Cat and Tiger objects // loop through array and call method // instanceOf Examples // is catty a Feline? // is tigris a Feline? // is felix a Cat? } // example2 method public static void example2() { // create a new Zoo // Adding different animals to the zoo // Displaying all animals in the zoo } // example3 method public static void example3() { // Create Object } // example4 method public static void example4() { // Create Object } } ``` ## Feline.java ```java // class header public class Feline { // private instance variable // constructor // constructor // methods } ``` ## Tiger.java ```java // class header public class Tiger extends Feline { // methods } ``` ## Cat.java ```java // class header public class Cat extends Feline { // constructors // methods } ``` ## Zoo.java ```java import java.util.*; // Base class representing a generic Animal (IS-A relationship) class Animal { // Method to make a generic animal sound public void makeSound() { System.out.println("Animals make sounds"); } } // Subclass representing a Bear (IS-A Animal) class Bear extends Animal { // Method specific to Bear public void growl() { System.out.println("Bears like to growl"); } } // Subclass representing a Lion (IS-A Animal) class Lion extends Animal { // Method specific to Lion public void roar() { System.out.println("Lions like to roar"); } } // Subclass representing an Elephant (IS-A Animal) class Elephant extends Animal { // Method specific to Elephant public void forage() { System.out.println("Elephants like to forage"); } } // Zoo class HAS-A relationship with a list of animals class Zoo { // ArrayList to store Animal objects // Constructor to initialize the list of animals // Add an animal to the zoo // Method to display the sounds of all animals in the zoo // Check if the animal is a Bear // Check if the animal is a Lion // Check if the animal is an Elephant } ``` ## Professions.java ```java import java.util.*; // Superclass // Subclass: // Subclass: // Subclass: // Subclass: // Main class public class Professions { public static void main(String[] args) { // create an ArrayList of Professions // Creating instances of each profession // Adding objects to the ArrayList // Loop through ArrayList of Professions using instanceof and calling methods } } ``` ## MainCharacter.java ```java class CharacterBase { void action() { System.out.println("Ready to fight! "); } } class Warrior extends CharacterBase { public Warrior() { System.out.println("Equipped with sword! "); super.action(); } } class Knight extends Warrior { public Knight() { System.out.println("For the kingdom!"); } } public class MainCharacter { public static void main(String[] args) { Knight k = new Knight(); } } ``` ## SquareDemo.java ```java // A class called Rectangle that has two instance variables, length and width, // a constructor that initializes them, and a method called draw that uses nested loops // to draw a length x width rectangle of stars. class Rectangle { private int length; private int width; // Constructor that initializes length and width public Rectangle(int l, int w) { length = l; width = w; } // Method to draw a rectangle of stars based on length and width public void draw() { for (int i = 0; i < length; i++) { for (int j = 0; j < width; j++) { System.out.print("* "); } System.out.println(); } System.out.println(); } // Add an area method to compute the area of the rectangle } // Make the class Square below inherit from Rectangle // Add a Square constructor with 1 argument for a side // that calls Rectangle's constructor with 2 arguments using super // Add another subclass called LongRectangle which inherits from Rectangle // but has the additional condition that the length is always 2 x the width public class SquareDemo { public static void main(String[] args) { // Create a Rectangle object and draw it Rectangle r = new Rectangle(3, 5); // System.out.println("Area of rectangle: " + r.area()); r.draw(); // Uncomment the objects to test the squares // Square s1 = new Square(1); // System.out.println("Area of square with side 1: " + s1.area()); // s1.draw(); // Square s2 = new Square(3); // System.out.println("Area of square with side 3: " + s2.area()); // s2.draw(); // System.out.println(); // Uncomment the objects to test the rectangle // LongRectangle lr = new LongRectangle(4); // System.out.println("Area of long rectangle with length 4: " + lr.area()); // lr.draw(); } } ``` --- # Agent Instructions This documentation is published with GitBook. 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