added ch13 practice problem (recursive merge sort) + progress on ch12 pokemon project

src/com/codefortomorrow/advanced/chapter13/examples/BinarySearch.java

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+package com.codefortomorrow.advanced.chapter13.examples;
+
+public class BinarySearch {
+
+    // Java implementation of recursive Binary Search
+    // Returns index of x if it is present in arr[l..
+    // r], else return -1
+    public static int binarySearch(int arr[], int l, int r, int x) {
+        if (r >= l) {
+            int mid = l + (r - l) / 2;
+
+            // If the element is present at the
+            // middle itself
+            if (arr[mid] == x) return mid;
+
+            // If element is smaller than mid, then
+            // it can only be present in left subarray
+            if (arr[mid] > x) return binarySearch(arr, l, mid - 1, x);
+
+            // Else the element can only be present
+            // in right subarray
+            return binarySearch(arr, mid + 1, r, x);
+        }
+
+        // We reach here when element is not present
+        // in array
+        return -1;
+    }
+
+    // Driver method to test above
+    public static void main(String args[]) {
+        int arr[] = { 2, 3, 4, 10, 40 };
+        int n = arr.length;
+        int x = 10;
+        int result = binarySearch(arr, 0, n - 1, x);
+        if (result == -1) System.out.println(
+            "Element not present"
+        ); else System.out.println("Element found at index " + result);
+    }
+    /* This code is contributed by Rajat Mishra
+    https://www.geeksforgeeks.org/binary-search/ */
+
+}

src/com/codefortomorrow/advanced/chapter13/examples/Fibonacci.java

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+package com.codefortomorrow.advanced.chapter13.examples;
+
+public class Fibonacci {
+
+    public static int fibonacciRecursion(int nthNumber) {
+        //use recursion
+        if (nthNumber == 0) {
+            return 0;
+        } else if (nthNumber == 1) {
+            return 1;
+        }
+        return (
+            fibonacciRecursion(nthNumber - 1) +
+            fibonacciRecursion(nthNumber - 2)
+        );
+    }
+
+    public static int fibonacciLoop(int nthNumber) {
+        //use loop
+        int previouspreviousNumber, previousNumber = 0, currentNumber = 1;
+        for (int i = 1; i < nthNumber; i++) {
+            previouspreviousNumber = previousNumber;
+            previousNumber = currentNumber;
+            currentNumber = previouspreviousNumber + previousNumber;
+        }
+        return currentNumber;
+    }
+    // Credit: https://dev.to/khalilsaboor/fibonacci-recursion-vs-iteration--474l
+}

src/com/codefortomorrow/advanced/chapter13/practice/RecurMergeSort.java

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+package com.codefortomorrow.advanced.chapter13.practice;
+
+public class RecurMergeSort {
+
+    public static void recurMergeSort(Comparable[] array, int start, int end) {}
+}

src/com/codefortomorrow/advanced/chapter13/solutions/RecurMergeSort.java

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+package com.codefortomorrow.advanced.chapter13.solutions;
+
+public class RecurMergeSort {
+
+    public static void recurMergeSort(Comparable[] array, int start, int end) {
+        if (start >= end) {
+            return;
+        }
+        int middle = (start + end) / 2;
+        recurMergeSort(array, start, middle);
+        recurMergeSort(array, middle + 1, end);
+        int i = start;
+        int j = middle + 1;
+        Comparable[] sortedArray = new Comparable[end - start + 1];
+        int k = 0;
+        while (i <= middle && j <= end) {
+            if (array[i].compareTo(array[j]) > 0) {
+                sortedArray[k] = array[i];
+                i++;
+            } else {
+                sortedArray[k] = array[j];
+                j++;
+            }
+            k++;
+        }
+        while (i <= middle) {
+            sortedArray[k] = array[i];
+            i++;
+            k++;
+        }
+        while (j <= end) {
+            sortedArray[k] = array[j];
+            j++;
+            k++;
+        }
+        k = 0;
+        for (int l = start; l <= end; l++) {
+            array[l] = sortedArray[k];
+            k++;
+        }
+    }
+}

src/com/codefortomorrow/advanced/chapter14/examples/BufferedReaderExample.java

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+package com.codefortomorrow.advanced.chapter14.examples;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+/**
+ * Source: https://beginnersbook.com/2014/01/how-to-read-file-in-java-using-bufferedreader/
+ */
+public class BufferedReaderExample {
+
+    public static void main(String[] args) {
+        BufferedReader br = null;
+        BufferedReader br2 = null;
+
+        try {
+            br = new BufferedReader(new FileReader("B:\\myfile.txt"));
+
+            //One way of reading the file
+            System.out.println("Reading the file using readLine() method:");
+            String contentLine = br.readLine();
+            while (contentLine != null) {
+                System.out.println(contentLine);
+                contentLine = br.readLine();
+            }
+
+            br2 = new BufferedReader(new FileReader("B:\\myfile2.txt"));
+
+            //Second way of reading the file
+            System.out.println("Reading the file using read() method:");
+            int num = 0;
+            char ch;
+            while ((num = br2.read()) != -1) {
+                ch = (char) num;
+                System.out.print(ch);
+            }
+        } catch (IOException ioe) {
+            ioe.printStackTrace();
+        }
+    }
+}

src/com/codefortomorrow/advanced/chapter14/practice/account/InvalidAgeException.java

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+package com.codefortomorrow.advanced.chapter14.practice.account;
+
+public class InvalidAgeException {}

src/com/codefortomorrow/advanced/chapter14/practice/account/InvalidPasswordException.java

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+package com.codefortomorrow.advanced.chapter14.practice.account;
+
+public class InvalidPasswordException {}

src/com/codefortomorrow/advanced/chapter14/practice/account/InvalidUsernameException.java

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+package com.codefortomorrow.advanced.chapter14.practice.account;
+
+public class InvalidUsernameException {}

src/com/codefortomorrow/advanced/chapter14/practice/account/Main.java

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+package com.codefortomorrow.advanced.chapter14.practice.account;
+
+import java.util.Scanner;
+
+public class Main {
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        System.out.println("Welcome to Account Creation!");
+        while (true) {
+            System.out.print("Enter username (4 to 10 characters): ");
+            String username = sc.next();
+            System.out.print("Enter age: ");
+            int age = sc.nextInt();
+            System.out.print("Enter password (4 to 10 characters): ");
+            String password = sc.next();
+            System.out.print("Confirm password (4 to 10 characters): ");
+            String confirmPassword = sc.next();
+
+            // TODO: try and catch to handle exceptions
+            createAccount(username, password, age, confirmPassword);
+            System.out.println("Account created successfully!");
+        }
+    }
+
+    public static void createAccount(
+        String username,
+        String password,
+        int age,
+        String confirmPassword
+    )
+        throws InvalidAgeException, InvalidPasswordException, InvalidUsernameException, PasswordMismatchException {
+        // TODO: complete
+    }
+}

src/com/codefortomorrow/advanced/chapter14/practice/account/PasswordMismatchException.java

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+package com.codefortomorrow.advanced.chapter14.practice.account;
+
+public class PasswordMismatchException {}

src/com/codefortomorrow/advanced/chapter14/solutions/account/InvalidAgeException.java

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+package com.codefortomorrow.advanced.chapter14.solutions.account;
+
+public class InvalidAgeException extends Exception {}

src/com/codefortomorrow/advanced/chapter14/solutions/account/InvalidPasswordException.java

@@ -0,0 +1,3 @@
+package com.codefortomorrow.advanced.chapter14.solutions.account;
+
+public class InvalidPasswordException extends Exception {}

src/com/codefortomorrow/advanced/chapter14/solutions/account/InvalidUsernameException.java

@@ -0,0 +1,3 @@
+package com.codefortomorrow.advanced.chapter14.solutions.account;
+
+public class InvalidUsernameException extends Exception {}

src/com/codefortomorrow/advanced/chapter14/solutions/account/Main.java

@@ -0,0 +1,57 @@
+package com.codefortomorrow.advanced.chapter14.solutions.account;
+
+import java.util.Scanner;
+
+public class Main {
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        System.out.println("Welcome to Account Creation!");
+        while (true) {
+            System.out.print("Enter username (4 to 10 characters): ");
+            String username = sc.next();
+            System.out.print("Enter age: ");
+            int age = sc.nextInt();
+            System.out.print("Enter password (4 to 10 characters): ");
+            String password = sc.next();
+            System.out.print("Confirm password (4 to 10 characters): ");
+            String confirmPassword = sc.next();
+
+            try {
+                createAccount(username, password, age, confirmPassword);
+                System.out.println("Account created successfully!");
+                break;
+            } catch (InvalidUsernameException e) {
+                System.out.println("Invalid username.");
+            } catch (InvalidPasswordException e) {
+                System.out.println("Invalid password.");
+            } catch (InvalidAgeException e) {
+                System.out.println("Must be 18 or older to create an account.");
+            } catch (PasswordMismatchException e) {
+                System.out.println("Passwords don't match!");
+            }
+        }
+    }
+
+    public static void createAccount(
+        String username,
+        String password,
+        int age,
+        String confirmPassword
+    )
+        throws InvalidAgeException, InvalidPasswordException, InvalidUsernameException, PasswordMismatchException {
+        if (username.length() < 4 || username.length() > 10) {
+            throw new InvalidUsernameException();
+        }
+        if (password.length() < 4 || password.length() > 10) {
+            throw new InvalidPasswordException();
+        }
+        if (age < 18) {
+            throw new InvalidAgeException();
+        }
+        if (!password.equals(confirmPassword)) {
+            throw new PasswordMismatchException();
+        }
+    }
+}

src/com/codefortomorrow/advanced/chapter14/solutions/account/PasswordMismatchException.java

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+package com.codefortomorrow.advanced.chapter14.solutions.account;
+
+public class PasswordMismatchException extends Exception {}

src/com/codefortomorrow/intermediate/chapter12/practice/pokemon/Battle.java

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+package com.codefortomorrow.intermediate.chapter12.practice.pokemon;
+
+import java.util.Scanner;
+
+public class Battle {
+    private Scanner sc = new Scanner(System.in);
+    private Pokemon pokemonOne;
+    private Pokemon pokemonTwo;
+    private int turn;
+
+    public Battle(Pokemon pokemonOne, Pokemon pokemonTwo) {
+        this.pokemonOne = pokemonOne;
+        this.pokemonTwo = pokemonTwo;
+        turn = 1;
+    }
+
+    public void runBattle() {
+        while (true) {
+            if (turn == 1) {
+                executeTurn(pokemonOne, pokemonTwo);
+            } else {
+                executeTurn(pokemonTwo, pokemonOne);
+            }
+            System.out.println(pokemonOne);
+            System.out.println(pokemonTwo);
+            if (
+                pokemonOne.getCurrentHP() <= 0 || pokemonTwo.getCurrentHP() <= 0
+            ) {
+                break;
+            }
+        }
+    }
+
+    public void executeTurn(Pokemon pokemon, Pokemon other) {
+        System.out.println("It's " + pokemon.getName() + "'s move!");
+
+        Move[] pokemonMoves = pokemon.getMoveList();
+        for (int i = 1; i <= pokemonMoves.length; i++) {
+            System.out.println(i + ": " + pokemonMoves[i - 1].getName());
+        }
+        System.out.print("Move #: ");
+        int move = sc.nextInt();
+        pokemon.attack(other, move - 1);
+        System.out.println();
+
+        if (turn == 1) {
+            turn = 0;
+        } else {
+            turn = 1;
+        }
+    }
+}