Tutorial 3

T3Q1-1/src/VendingMachineApp.java

@@ -0,0 +1,14 @@
+public class VendingMachineApp {
+
+    public static void main(String[] args)
+    {
+        double drinkCost = 0;
+        double amountInserted = 0.0;
+
+        VendingMachine vendingMachine = new VendingMachine();
+        drinkCost = vendingMachine.selectDrink();
+        amountInserted = vendingMachine.insertCoins(drinkCost);
+        vendingMachine.checkChange(amountInserted, drinkCost);
+        vendingMachine.printReceipt();
+    }
+}

T3Q1-2/src/VendingMachine.java

@@ -0,0 +1,104 @@
+import java.util.Scanner;
+
+public class VendingMachine {
+
+    public VendingMachine() {}
+
+    public double selectDrink() {
+        int drinkSelection;
+        double drinkCost = 0;
+
+        drinkSelection = presentDrinkMenu();
+
+        if (drinkSelection == 1) drinkCost = 3.00;
+        else if (drinkSelection == 2) drinkCost = 1.00;
+        else if (drinkSelection == 3) drinkCost = 5.00;
+        return drinkCost;
+    }
+
+    public double insertCoins(double drinkCost) {
+        double amount = 0.0;
+
+        Scanner sc = new Scanner(System.in);
+        printCoinOptions();
+
+        do {
+            char coin = sc.next().charAt(0);
+            amount += processCoinAmount(coin);
+            System.out.printf("Coins inserted: %.2f \n", amount);
+        } while (amount < drinkCost);
+        return amount;
+    }
+
+    public void checkChange(double amount, double drinkCost)
+    {
+        double change = 0.0;
+        if (amount > drinkCost)
+        {
+            change = amount - drinkCost;
+            System.out.printf("Change $ %.2f \n", change);
+        }
+    }
+
+    public void printReceipt()
+    {
+        System.out.println("Please collect your drink");
+        System.out.println("Thank you!!");
+    }
+
+    private int presentDrinkMenu() {
+        Scanner sc = new Scanner(System.in);
+
+        int drinkSelection;
+
+        System.out.println("====== Vending Machine ======");
+        System.out.println("|1. Buy Beer ($3.00)        |");
+        System.out.println("|2. Buy Coke ($1.00)        |");
+        System.out.println("|3. Buy Green Tea ($5.00)   |");
+        System.out.println("|============================");
+
+        do {
+            System.out.println("Please enter selection: ");
+            drinkSelection = sc.nextInt();
+        } while (drinkSelection < 1 || drinkSelection > 3);
+
+        return drinkSelection;
+    }
+
+    private void printCoinOptions() {
+        System.out.println("Please insert coins: ");
+        System.out.println("========== Coins Input ===========");
+        System.out.println("|Enter 'Q' for ten cents input   |");
+        System.out.println("|Enter 'T' for twenty cents input|");
+        System.out.println("|Enter 'F' for fifty cents input |");
+        System.out.println("|Enter 'N' for a dollar input    |");
+        System.out.println("==================================");
+    }
+
+    private double processCoinAmount(char coin) {
+        /*
+        Note. The code below is just an enhanced way of writing the following:
+
+        switch (coin)
+        {
+            case 'Q': case 'q': return 0.10;
+            case 'T': case 't': return 0.20;
+            case 'F': case 'f': return 0.50;
+            case 'N': case 'n': return 1.00;
+        }
+        return 0.0;
+
+        This enhanced way or writing switch-cases was introduced in Java 12 and Java 13 (we are currently at Java LTS 22, with Java 23 and Java 24 under early-access);
+        The "->" was introduced in Java 8. It denotes a Lambda expression: https://www.w3schools.com/java/java_lambda.asp
+
+        The Switch with a lambda-like syntax expression was introduced in Java 14: https://www.javacodegeeks.com/2020/05/switch-as-an-expression-in-java-with-lambda-like-syntax.html
+         */
+        return switch (coin) {
+            case 'Q', 'q' -> 0.10;
+            case 'T', 't' -> 0.20;
+            case 'F', 'f' -> 0.50;
+            case 'N', 'n' -> 1.00;
+            default -> 0.0;
+        };
+    }
+}

T3Q1-2/src/VendingMachineApp.java

@@ -0,0 +1,14 @@
+public class VendingMachineApp {
+
+    public static void main(String[] args)
+    {
+        double drinkCost = 0;
+        double amountInserted = 0.0;
+
+        VendingMachine vendingMachine = new VendingMachine();
+        drinkCost = vendingMachine.selectDrink();
+        amountInserted = vendingMachine.insertCoins(drinkCost);
+        vendingMachine.checkChange(amountInserted, drinkCost);
+        vendingMachine.printReceipt();
+    }
+}

T3Q1-3/src/VendingMachine.java

@@ -0,0 +1,117 @@
+import java.util.Scanner;
+/*
+You could also use "import drinks.*" instead of the 4 lines below
+ */
+import drinks.Beer;
+import drinks.Coke;
+import drinks.Drink;
+import drinks.GreenTea;
+
+public class VendingMachine {
+    private static final Drink[] availableDrinks = new Drink[3];
+    int drinkSelection = 0;
+
+    public VendingMachine() {
+        availableDrinks[0] = new Beer();
+        availableDrinks[1] = new Coke();
+        availableDrinks[2] = new GreenTea();
+    }
+
+    public double selectDrink() {
+        drinkSelection = presentDrinkMenu() - 1; // This " - 1 " is to keep "drinkSelection" within the "availableDrinks" array range
+        return availableDrinks[drinkSelection].getPrice();
+    }
+
+    public double insertCoins() {
+        double amount = 0.0;
+
+        Scanner sc = new Scanner(System.in);
+        printCoinOptions();
+
+        do {
+            char coin = sc.next().charAt(0);
+            amount += processCoinAmount(coin);
+            System.out.printf("Coins inserted: %.2f \n", amount);
+        } while (amount < availableDrinks[drinkSelection].getPrice());
+        return amount;
+    }
+
+    public void checkChange(double amount)
+    {
+        double change = 0.0;
+        if (amount > availableDrinks[drinkSelection].getPrice())
+        {
+            change = amount - availableDrinks[drinkSelection].getPrice();
+            System.out.printf("Change $ %.2f \n", change);
+        }
+    }
+
+    public void printReceipt()
+    {
+        System.out.println("Please collect your drink");
+        System.out.println("Thank you!!");
+    }
+
+    private Integer presentDrinkMenu() {
+        Scanner sc = new Scanner(System.in);
+        int drinkSelection;
+
+        System.out.print("====== Vending Machine ====== \n");
+        /*
+         Note. The for loop below is just an enhanced way of writing the following:
+
+            for (int i = 0; i < availableDrinks.length; i++) {
+               System.out.printf("|%d. Buy %s ($%.2f)   \n", i + 1, availableDrinks[i].getName(), availableDrinks[i].getPrice());
+            }
+         */
+        int i = 1;
+        for (Drink drink : availableDrinks) {
+            System.out.printf("|%d. Buy %s ($%.2f)   \n", i++, drink.getName(), drink.getPrice());
+        }
+        System.out.print("|============================ \n");
+
+        do {
+            System.out.println("Please enter selection: ");
+            drinkSelection = sc.nextInt();
+        } while (drinkSelection < 1 || drinkSelection > (availableDrinks.length + 1));
+
+        return drinkSelection;
+    }
+
+    private void printCoinOptions() {
+        System.out.println("Please insert coins: ");
+        System.out.println("========== Coins Input ===========");
+        System.out.println("|Enter 'Q' for ten cents input   |");
+        System.out.println("|Enter 'T' for twenty cents input|");
+        System.out.println("|Enter 'F' for fifty cents input |");
+        System.out.println("|Enter 'N' for a dollar input    |");
+        System.out.println("==================================");
+    }
+
+    private double processCoinAmount(char coin) {
+        /*
+        Note. The code below is just an enhanced way of writing the following:
+
+        switch (coin)
+        {
+            case 'Q': case 'q': return 0.10;
+            case 'T': case 't': return 0.20;
+            case 'F': case 'f': return 0.50;
+            case 'N': case 'n': return 1.00;
+        }
+        return 0.0;
+
+        This enhanced way or writing switch-cases was introduced in Java 12 and Java 13 (we are currently at Java LTS 22, with Java 23 and Java 24 under early-access);
+        The "->" was introduced in Java 8. It denotes a Lambda expression: https://www.w3schools.com/java/java_lambda.asp
+
+        The Switch with a lambda-like syntax expression was introduced in Java 14: https://www.javacodegeeks.com/2020/05/switch-as-an-expression-in-java-with-lambda-like-syntax.html
+         */
+        return switch (coin) {
+            case 'Q', 'q' -> 0.10;
+            case 'T', 't' -> 0.20;
+            case 'F', 'f' -> 0.50;
+            case 'N', 'n' -> 1.00;
+            default -> 0.0;
+        };
+    }
+}

T3Q1-3/src/VendingMachineApp.java

@@ -0,0 +1,13 @@
+public class VendingMachineApp {
+
+    public static void main(String[] args)
+    {
+        double amountInserted = 0.0;
+
+        VendingMachine vendingMachine = new VendingMachine();
+        vendingMachine.selectDrink();
+        amountInserted = vendingMachine.insertCoins();
+        vendingMachine.checkChange(amountInserted);
+        vendingMachine.printReceipt();
+    }
+}

T3Q1-3/src/drinks/Beer.java

@@ -0,0 +1,10 @@
+package drinks;
+
+public class Beer extends Drink {
+    private static final String NAME = "Beer";
+    private static final double PRICE = 3.0;
+
+    public Beer() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-3/src/drinks/Coke.java

@@ -0,0 +1,10 @@
+package drinks;
+
+public class Coke extends Drink {
+    private static final String NAME = "Coke";
+    private static final double PRICE = 1.0;
+
+    public Coke() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-3/src/drinks/Drink.java

@@ -0,0 +1,19 @@
+package drinks;
+
+public class Drink {
+    private String name;
+    private double price;
+
+    public Drink(String name, double price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public String getName() {
+        return name;
+    }
+}

T3Q1-3/src/drinks/GreenTea.java

@@ -0,0 +1,10 @@
+package drinks;
+
+public class GreenTea extends Drink {
+    private static final String NAME = "Green Tea";
+    private static final double PRICE = 5.0;
+
+    public GreenTea() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-4/src/VendingMachine.java

@@ -0,0 +1,124 @@
+import drinks.Beer;
+import drinks.Coke;
+import drinks.Drink;
+import drinks.GreenTea;
+
+import java.util.Scanner;
+
+public class VendingMachine {
+    private static final Drink[] availableDrinks = new Drink[3];
+    int drinkSelection = 0;
+
+    public VendingMachine() {
+        availableDrinks[0] = new Beer();
+        availableDrinks[1] = new Coke();
+        availableDrinks[2] = new GreenTea();
+    }
+
+    public void start() {
+        // This is an infinite loop. This is quite common in applications that must run 24/7
+        do {
+            double amountInserted = 0.0;
+            selectDrink();
+            insertCoins();
+            checkChange(amountInserted);
+            printReceipt();
+        } while (true);
+    }
+
+    private void selectDrink() {
+        drinkSelection = presentDrinkMenu();
+    }
+
+    private void insertCoins() {
+        double amount = 0.0;
+
+        Scanner sc = new Scanner(System.in);
+        printCoinOptions();
+
+        do {
+            char coin = sc.next().charAt(0);
+            amount += processCoinAmount(coin);
+            System.out.printf("Coins inserted: %.2f \n", amount);
+        } while (amount < availableDrinks[drinkSelection].getPrice());
+    }
+
+    private void checkChange(double amount)
+    {
+        double change = 0.0;
+        if (amount > availableDrinks[drinkSelection].getPrice())
+        {
+            change = amount - availableDrinks[drinkSelection].getPrice();
+            System.out.printf("Change $ %.2f \n", change);
+        }
+    }
+
+    private void printReceipt()
+    {
+        System.out.println("Please collect your drink");
+        System.out.println("Thank you!!");
+    }
+
+    private Integer presentDrinkMenu() {
+        Scanner sc = new Scanner(System.in);
+        int drinkSelection;
+
+        System.out.print("====== Vending Machine ====== \n");
+        /*
+         Note. The for loop below is just an enhanced way of writing the following:
+
+            for (int i = 0; i < availableDrinks.length; i++) {
+               System.out.printf("|%d. Buy %s ($%.2f)   \n", i + 1, availableDrinks[i].getName(), availableDrinks[i].getPrice());
+            }
+         */
+        int i = 1;
+        for (Drink drink : availableDrinks) {
+            System.out.printf("|%d. Buy %s ($%.2f)   \n", i++, drink.getName(), drink.getPrice());
+        }
+        System.out.print("|============================ \n");
+
+        do {
+            System.out.println("Please enter selection: ");
+            drinkSelection = sc.nextInt() - 1; // This " - 1 " is to keep "drinkSelection" within the "availableDrinks" array range;
+        } while (drinkSelection < 0 || drinkSelection > availableDrinks.length);
+
+        return drinkSelection ;
+    }
+
+    private void printCoinOptions() {
+        System.out.println("Please insert coins: ");
+        System.out.println("========== Coins Input ===========");
+        System.out.println("|Enter 'Q' for ten cents input   |");
+        System.out.println("|Enter 'T' for twenty cents input|");
+        System.out.println("|Enter 'F' for fifty cents input |");
+        System.out.println("|Enter 'N' for a dollar input    |");
+        System.out.println("==================================");
+    }
+
+    private double processCoinAmount(char coin) {
+        /*
+        Note. The code below is just an enhanced way of writing the following:
+
+        switch (coin)
+        {
+            case 'Q': case 'q': return 0.10;
+            case 'T': case 't': return 0.20;
+            case 'F': case 'f': return 0.50;
+            case 'N': case 'n': return 1.00;
+        }
+        return 0.0;
+
+        This enhanced way or writing switch-cases was introduced in Java 12 and Java 13 (we are currently at Java LTS 22, with Java 23 and Java 24 under early-access);
+        The "->" was introduced in Java 8. It denotes a Lambda expression: https://www.w3schools.com/java/java_lambda.asp
+
+        The Switch with a lambda-like syntax expression was introduced in Java 14: https://www.javacodegeeks.com/2020/05/switch-as-an-expression-in-java-with-lambda-like-syntax.html
+         */
+        return switch (coin) {
+            case 'Q', 'q' -> 0.10;
+            case 'T', 't' -> 0.20;
+            case 'F', 'f' -> 0.50;
+            case 'N', 'n' -> 1.00;
+            default -> 0.0;
+        };
+    }
+}

T3Q1-4/src/VendingMachineApp.java

@@ -0,0 +1,9 @@
+public class VendingMachineApp {
+
+    public static void main(String[] args)
+    {
+        VendingMachine vendingMachine = new VendingMachine();
+        vendingMachine.start();
+    }
+
+}

T3Q1-4/src/drinks/Beer.java

@@ -0,0 +1,10 @@
+package drinks;
+
+public class Beer extends Drink {
+    private static final String NAME = "Beer";
+    private static final double PRICE = 3.0;
+
+    public Beer() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-4/src/drinks/Coke.java

@@ -0,0 +1,10 @@
+package drinks;
+
+public class Coke extends Drink {
+    private static final String NAME = "Coke";
+    private static final double PRICE = 1.0;
+
+    public Coke() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-4/src/drinks/Drink.java

@@ -0,0 +1,19 @@
+package drinks;
+
+public class Drink {
+    private String name;
+    private double price;
+
+    public Drink(String name, double price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public String getName() {
+        return name;
+    }
+}

T3Q1-4/src/drinks/GreenTea.java

@@ -0,0 +1,10 @@
+package drinks;
+
+public class GreenTea extends Drink {
+    private static final String NAME = "Green Tea";
+    private static final double PRICE = 5.0;
+
+    public GreenTea() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-extra1/src/VendingMachine.java

@@ -0,0 +1,100 @@
+import drinks.*;
+import coins.*;
+
+import java.util.Scanner;
+
+public class VendingMachine {
+    private static final Drink[] availableDrinks = new Drink[3];
+    private static final Coin[] acceptableCoins = new Coin[4];
+    private static final Scanner sc = new Scanner(System.in);
+
+    int drinkSelection = 0;
+    private boolean isRunning = true;
+
+    public VendingMachine()
+    {
+        availableDrinks[0] = new Beer();
+        availableDrinks[1] = new Coke();
+        availableDrinks[2] = new GreenTea();
+
+        acceptableCoins[0] = new Ten();
+        acceptableCoins[1] = new Twenty();
+        acceptableCoins[2] = new Fifty();
+        acceptableCoins[3] = new Dollar();
+    }
+
+    public void start()
+    {
+        while (isRunning)
+        {
+            collectOrder();
+            checkChange(collectCoins());
+            printReceipt();
+        }
+    }
+
+    public void stop()
+    {
+        isRunning = false;
+    }
+
+    private void collectOrder()
+    {
+        System.out.print("====== Vending Machine ====== \n");
+        int i = 1;
+        for (Drink drink : availableDrinks)
+            System.out.printf("|%d. Buy %s ($%.2f)   \n", i++, drink.getName(), drink.getPrice());
+        System.out.print("|============================ \n");
+
+        do {
+            System.out.println("Please enter selection: ");
+            drinkSelection = sc.nextInt() - 1;
+        } while (drinkSelection < 0 || drinkSelection > availableDrinks.length);
+    }
+
+    private double collectCoins()
+    {
+        double amount = 0.0;
+        presentCoinMenu();
+
+        do {
+            amount += processCoinAmount();
+            System.out.printf("Coins inserted: %.2f \n", amount);
+        } while (amount < availableDrinks[drinkSelection].getPrice());
+
+        return amount;
+    }
+
+    private void checkChange(double amount)
+    {
+        if (amount > availableDrinks[drinkSelection].getPrice())
+            System.out.printf("Change $ %.2f \n", amount - availableDrinks[drinkSelection].getPrice());
+    }
+
+    private void printReceipt()
+    {
+        System.out.println("Please collect your drink");
+        System.out.println("Thank you!!");
+    }
+
+    private void presentCoinMenu()
+    {
+        System.out.println("Please insert coins: ");
+        System.out.println("========== Coins Input ===========");
+        for (Coin coin : acceptableCoins)
+            System.out.printf("|Enter '%c' for %s input \n", coin.getSymbol(), coin.getDescription());
+        System.out.println("==================================");
+    }
+
+    private double processCoinAmount()
+    {
+        char insertedCoin = sc.next().charAt(0);
+        insertedCoin = Character.toUpperCase(insertedCoin);
+
+        for (Coin coin : acceptableCoins)
+            if (insertedCoin == coin.getSymbol())
+                return coin.getValue();
+
+        return 0.0;
+    }
+}

T3Q1-extra1/src/VendingMachineApp.java

@@ -0,0 +1,9 @@
+public class VendingMachineApp {
+
+    public static void main(String[] args)
+    {
+        VendingMachine vendingMachine = new VendingMachine();
+        vendingMachine.start();
+    }
+
+}

T3Q1-extra1/src/coins/Coin.java

@@ -0,0 +1,30 @@
+package coins;
+
+public class Coin
+{
+    private final double value;
+    private final char symbol;
+    private final String description;
+
+    public Coin(double value, char symbol, String description)
+    {
+        this.value = value;
+        this.symbol = symbol;
+        this.description = description;
+    }
+
+    public double getValue()
+    {
+        return value;
+    }
+
+    public char getSymbol()
+    {
+        return symbol;
+    }
+
+    public String getDescription()
+    {
+        return description;
+    }
+}

T3Q1-extra1/src/coins/Dollar.java

@@ -0,0 +1,13 @@
+package coins;
+
+public class Dollar extends Coin
+{
+    private static final double VALUE = 1.00;
+    private static final char SYMBOL = 'N';
+    private static final String DESCRIPTION = "a dollar";
+
+    public Dollar()
+    {
+        super(VALUE, SYMBOL, DESCRIPTION);
+    }
+}

T3Q1-extra1/src/coins/Fifty.java

@@ -0,0 +1,13 @@
+package coins;
+
+public class Fifty extends Coin
+{
+    private static final double VALUE = 0.50;
+    private static final char SYMBOL = 'F';
+    private static final String DESCRIPTION = "fifty cents";
+
+    public Fifty()
+    {
+        super(VALUE, SYMBOL, DESCRIPTION);
+    }
+}

T3Q1-extra1/src/coins/Ten.java

@@ -0,0 +1,13 @@
+package coins;
+
+public class Ten extends Coin
+{
+    private static final double VALUE = 0.10;
+    private static final char SYMBOL = 'Q';
+    private static final String DESCRIPTION = "ten cents";
+
+    public Ten()
+    {
+        super(VALUE, SYMBOL, DESCRIPTION);
+    }
+}

T3Q1-extra1/src/coins/Twenty.java

@@ -0,0 +1,13 @@
+package coins;
+
+public class Twenty extends Coin
+{
+    private static final double VALUE = 0.20;
+    private static final char SYMBOL = 'T';
+    private static final String DESCRIPTION = "twenty cents";
+
+    public Twenty()
+    {
+        super(VALUE, SYMBOL, DESCRIPTION);
+    }
+}

T3Q1-extra1/src/drinks/Beer.java

@@ -0,0 +1,11 @@
+package drinks;
+
+public class Beer extends Drink
+{
+    private static final String NAME = "Beer";
+    private static final double PRICE = 3.0;
+
+    public Beer() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-extra1/src/drinks/Coke.java

@@ -0,0 +1,11 @@
+package drinks;
+
+public class Coke extends Drink
+{
+    private static final String NAME = "Coke";
+    private static final double PRICE = 1.0;
+
+    public Coke() {
+        super(NAME, PRICE);
+    }
+}

T3Q1-extra1/src/drinks/Drink.java

@@ -0,0 +1,23 @@
+package drinks;
+
+public class Drink
+{
+    private final String name;
+    private final double price;
+
+    public Drink(String name, double price)
+    {
+        this.name = name;
+        this.price = price;
+    }
+
+    public double getPrice()
+    {
+        return price;
+    }
+
+    public String getName()
+    {
+        return name;
+    }
+}

T3Q1-extra1/src/drinks/GreenTea.java

@@ -0,0 +1,11 @@
+package drinks;
+
+public class GreenTea extends Drink
+{
+    private static final String NAME = "Green Tea";
+    private static final double PRICE = 5.0;
+
+    public GreenTea() {
+        super(NAME, PRICE);
+    }
+}

T3Q2-1/T3Q2-1.iml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="jdk" jdkName="openjdk-22" jdkType="JavaSDK" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

T3Q2-1/src/Circle.java

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+public class Circle extends Point {
+    private double radius;
+
+    public Circle() { radius = 1; }
+    public Circle(double radius) { this.radius = radius; }
+    public Circle(int x, int y, double radius) { super(x, y); this.radius = radius; }
+    public Circle(int x, int y) { super(x, y); radius = 1; }
+
+    public double getRadius() { return radius; }
+    public void setRadius(double radius) { this.radius = radius; }
+
+    public double area() { return Math.PI * radius * radius; }
+    public String toString() { return "Circle of radius " + radius + " at point [" + x + "," + y + "]"; }
+}

T3Q2-1/src/Cylinder.java

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+public class Cylinder extends Circle {
+    private double height;
+
+    public Cylinder() { height = 1; }
+    public Cylinder(double height) { this.height = height;}
+    public Cylinder(double radius, double height) { super(radius); this.height = height; }
+    public Cylinder(int x, int y, double radius) { super(x, y, radius); height = 1; }
+    public Cylinder(int x, int y, double radius, double height) { super(x, y, radius); this.height = height; }
+
+    public double getHeight() { return height; }
+    public void setHeight(double height) { this.height = height; }
+
+    public double area() { return 2 * (super.area() + Math.PI * super.getRadius() * height); }
+    public double volume() { return super.area() * height; };
+
+    public String toString() { return "Cylinder of height " + height + ", radius " + getRadius() + " at point [" + x + "," + y + "]"; }
+}

T3Q2-1/src/Test.java

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+public class Test {
+
+    public static void main(String[] args) {
+        Circle testCircle1 = new Circle();
+        Circle testCircle2 = new Circle(2, 4, 35);
+        Cylinder testCylinder1 = new Cylinder();
+        Cylinder testCylinder2 = new Cylinder(3, 3, 8, 20);
+
+        System.out.println("Area of Circle 1 = " + testCircle1.area());
+        System.out.println("Area of Circle 2 = " + testCircle2.area());
+        System.out.println("Surface Area of Cylinder 1 = " + testCylinder1.area());
+        System.out.println("Surface Area of Cylinder 2 = " + testCylinder2.area());
+        System.out.println("Volume of Cylinder 1 = " + testCylinder1.volume());
+        System.out.println("Volume of Cylinder 2 = " + testCylinder2.volume());
+
+        System.out.println("Description of Circle 1 = " + testCircle1.toString());
+        System.out.println("Description of Circle 2 = " + testCircle2.toString());
+        System.out.println("Description of Cylinder 1 = " + testCylinder1.toString());
+        System.out.println("Description of Cylinder 2 = " + testCylinder2.toString());
+    }
+}

T3Q2-2/src/Circle.java

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+public class Circle extends Point {
+    private double radius;
+
+    public Circle() { radius = 1; }
+    public Circle(double radius) { this.radius = radius; }
+    public Circle(int x, int y, double radius) { super(x, y); this.radius = radius; }
+    public Circle(int x, int y) { super(x, y); radius = 1; }
+
+    public double getRadius() { return radius; }
+    public void setRadius(double radius) { this.radius = radius; }
+
+    public double area() { return Math.PI * radius * radius; }
+    public String toString() { return String.format("Circle of radius %.2f at point %s", radius, super.toString()); }
+}

T3Q2-2/src/Cylinder.java

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+public class Cylinder extends Circle {
+    private double height;
+
+    public Cylinder() { height = 1; }
+    public Cylinder(double height) { this.height = height;}
+    public Cylinder(double radius, double height) { super(radius); this.height = height; }
+    public Cylinder(int x, int y, double radius) { super(x, y, radius); height = 1; }
+    public Cylinder(int x, int y, double radius, double height) { super(x, y, radius); this.height = height; }
+
+    public double getHeight() { return height; }
+    public void setHeight(double height) { this.height = height; }
+
+    public double area() { return 2 * (super.area() + Math.PI * super.getRadius() * height); }
+    public double volume() { return super.area() * height; };
+
+    // WRONG - It goes against Java's encapsulation rules. A class should only have access to its parent, without bypassing it.
+    public String toString() { return String.format("Cylinder of height %.2f, radius %.2f at point %s", height, getRadius(), super.super.toString()); }
+}

T3Q2-2/src/Point.java

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+public class Point {
+    protected int x, y;
+
+    public Point() { x = 0; y = 0; }
+    public Point(int x, int y) { this.x = x; this.y = y; }
+
+    public void setPoint(int x, int y) { this.x = x; this.y = y; }
+
+    public int getX() { return x; }
+    public int getY() { return y; }
+
+    public String toString() { return String.format("[%d,%d]", x, y); }
+}

T3Q2-2/src/Test.java

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+public class Test {
+
+    public static void main(String[] args) {
+        Circle testCircle1 = new Circle();
+        Circle testCircle2 = new Circle(2, 4, 35);
+        Cylinder testCylinder1 = new Cylinder();
+        Cylinder testCylinder2 = new Cylinder(3, 3, 8, 20);
+
+        System.out.println("Area of Circle 1 = " + testCircle1.area());
+        System.out.println("Area of Circle 2 = " + testCircle2.area());
+        System.out.println("Surface Area of Cylinder 1 = " + testCylinder1.area());
+        System.out.println("Surface Area of Cylinder 2 = " + testCylinder2.area());
+        System.out.println("Volume of Cylinder 1 = " + testCylinder1.volume());
+        System.out.println("Volume of Cylinder 2 = " + testCylinder2.volume());
+
+        System.out.println("Description of Circle 1 = " + testCircle1.toString());
+        System.out.println("Description of Circle 2 = " + testCircle2.toString());
+        System.out.println("Description of Cylinder 1 = " + testCylinder1.toString());
+        System.out.println("Description of Cylinder 2 = " + testCylinder2.toString());
+    }
+}

T3Q2-3/src/Circle.java

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+public class Circle extends Point {
+    private double radius;
+
+    public Circle() { radius = 1; }
+    public Circle(double radius) { this.radius = radius; }
+    public Circle(int x, int y, double radius) { super(x, y); this.radius = radius; }
+    public Circle(int x, int y) { super(x, y); radius = 1; }
+
+    public double getRadius() { return radius; }
+    public void setRadius(double radius) { this.radius = radius; }
+
+    public double area() { return Math.PI * radius * radius; }
+    public String toString() { return String.format("Circle of radius %.2f at point %s", radius, super.toString()); }
+}

T3Q2-3/src/Cylinder.java

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+public class Cylinder extends Circle {
+    private double height;
+
+    public Cylinder() { height = 1; }
+    public Cylinder(double height) { this.height = height;}
+    public Cylinder(double radius, double height) { super(radius); this.height = height; }
+    public Cylinder(int x, int y, double radius) { super(x, y, radius); height = 1; }
+    public Cylinder(int x, int y, double radius, double height) { super(x, y, radius); this.height = height; }
+
+    public double getHeight() { return height; }
+    public void setHeight(double height) { this.height = height; }
+
+    public double area() { return 2 * (super.area() + Math.PI * super.getRadius() * height); }
+    public double volume() { return super.area() * height; };
+
+    public String toString() { return String.format("Cylinder of height %.2f, radius %.2f at point %s", height, getRadius(), printPoint() ); }
+}

T3Q2-3/src/Point.java

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+public class Point {
+    protected int x, y;
+
+    public Point() { x = 0; y = 0; }
+    public Point(int x, int y) { this.x = x; this.y = y; }
+
+    public void setPoint(int x, int y) { this.x = x; this.y = y; }
+
+    public int getX() { return x; }
+    public int getY() { return y; }
+
+    public String toString() { return String.format("[%d,%d]", x, y); }
+    public String printPoint() { return toString(); }
+}

T3Q2-3/src/Test.java

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+public class Test {
+
+    public static void main(String[] args) {
+        Circle testCircle1 = new Circle();
+        Circle testCircle2 = new Circle(2, 4, 35);
+        Cylinder testCylinder1 = new Cylinder();
+        Cylinder testCylinder2 = new Cylinder(3, 3, 8, 20);
+
+        System.out.println("Area of Circle 1 = " + testCircle1.area());
+        System.out.println("Area of Circle 2 = " + testCircle2.area());
+        System.out.println("Surface Area of Cylinder 1 = " + testCylinder1.area());
+        System.out.println("Surface Area of Cylinder 2 = " + testCylinder2.area());
+        System.out.println("Volume of Cylinder 1 = " + testCylinder1.volume());
+        System.out.println("Volume of Cylinder 2 = " + testCylinder2.volume());
+
+        System.out.println("Description of Circle 1 = " + testCircle1.toString());
+        System.out.println("Description of Circle 2 = " + testCircle2.toString());
+        System.out.println("Description of Cylinder 1 = " + testCylinder1.toString());
+        System.out.println("Description of Cylinder 2 = " + testCylinder2.toString());
+    }
+}

T3Q2-4/src/Circle.java

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+public class Circle {
+    protected Point center = new Point();
+    protected double radius;
+
+    public Circle() { radius = 1; }
+    public Circle(double radius) { this.radius = radius; }
+    public Circle(int x, int y, double radius) { center.setPoint(x, y); this.radius = radius; }
+    public Circle(int x, int y) { center.setPoint(x, y); radius = 1; }
+
+    public double getRadius() { return radius; }
+    public void setRadius(double radius) { this.radius = radius; }
+
+    public double area() { return Math.PI * radius * radius; }
+    public String toString() { return String.format("Circle of radius %.2f at point %s", radius, center.toString()); }
+}

T3Q2-4/src/Cylinder.java

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+public class Cylinder extends Circle {
+    private double height;
+
+    public Cylinder() { height = 1; }
+    public Cylinder(double height) { this.height = height;}
+    public Cylinder(double radius, double height) { super(radius); this.height = height; }
+    public Cylinder(int x, int y, double radius) { super(x, y, radius); height = 1; }
+    public Cylinder(int x, int y, double radius, double height) { super(x, y, radius); this.height = height; }
+
+    public double getHeight() { return height; }
+    public void setHeight(double height) { this.height = height; }
+
+    public double area() { return 2 * (super.area() + Math.PI * super.getRadius() * height); }
+    public double volume() { return super.area() * height; };
+
+    public String toString() { return String.format("Cylinder of height %.2f, radius %.2f at point %s", height, getRadius(), center.toString() ); }
+}

T3Q2-4/src/Point.java

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+public class Point {
+    protected int x, y;
+
+    public Point() { x = 0; y = 0; }
+    public Point(int x, int y) { this.x = x; this.y = y; }
+
+    public void setPoint(int x, int y) { this.x = x; this.y = y; }
+
+    public int getX() { return x; }
+    public int getY() { return y; }
+
+    public String toString() { return String.format("[%d,%d]", x, y); }
+}

T3Q2-4/src/Test.java

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+public class Test {
+
+    public static void main(String[] args) {
+        Circle testCircle1 = new Circle();
+        Circle testCircle2 = new Circle(2, 4, 35);
+        Cylinder testCylinder1 = new Cylinder();
+        Cylinder testCylinder2 = new Cylinder(3, 3, 8, 20);
+
+        System.out.printf("Area of Circle 1 = %.2f\n", testCircle1.area());
+        System.out.printf("Area of Circle 2 = %.2f\n", testCircle2.area());
+        System.out.printf("Surface Area of Cylinder 1 = %.2f\n", testCylinder1.area());
+        System.out.printf("Surface Area of Cylinder 2 = %.2f\n", testCylinder2.area());
+        System.out.printf("Volume of Cylinder 1 = %.2f\n", testCylinder1.volume());
+        System.out.printf("Volume of Cylinder 2 = %.2f\n", testCylinder2.volume());
+
+        System.out.println("Description of Circle 1 = " + testCircle1);
+        System.out.println("Description of Circle 2 = " + testCircle2);
+        System.out.println("Description of Cylinder 1 = " + testCylinder1);
+        System.out.println("Description of Cylinder 2 = " + testCylinder2);
+    }
+}