Done. Quiz4.

src/main/java/rocks/zipcode/quiz4/arrays/ArrayUtils.java

@@ -1,22 +1,33 @@
 package rocks.zipcode.quiz4.arrays;
 
+import java.util.Arrays;
+
 /**
  * @author leon on 01/01/2019.
  */
 public class ArrayUtils {
     public static String getMiddleElement(String[] values) {
-        return null;
+        return values[values.length/2];
     }
 
     public static String[] removeMiddleElement(String[] values) {
-        return null;
+
+        String[] result = new String[values.length-1];
+        int count = 0;
+        for (int i = 0; i < values.length; i++) {
+            if(!values[i].equals(getMiddleElement(values))){
+                result[count] = values[i];
+                count++;
+            }
+        }
+        return result;
     }
 
     public static String getLastElement(String[] values) {
-        return null;
+        return values[values.length-1];
     }
 
     public static String[] removeLastElement(String[] values) {
-        return null;
+        return Arrays.copyOf(values,values.length-1);
     }
 }

src/main/java/rocks/zipcode/quiz4/collections/WordCounter.java

@@ -1,12 +1,23 @@
 package rocks.zipcode.quiz4.collections;
 
+import java.util.HashMap;
 import java.util.Map;
 
 public class WordCounter {
+    Map<String, Integer> myMap = new HashMap<>();
+
     public WordCounter(String... strings) {
+        for (String x : strings) {
+            Integer count = 1;
+            if (myMap.containsKey(x)) {
+                count = myMap.get(x);
+                count++;
+            }
+            myMap.put(x, count);
+        }
     }
 
     public Map<String, Integer> getWordCountMap() {
-        return null;
+        return myMap;
     }
 }

src/main/java/rocks/zipcode/quiz4/collections/culonary/Curry.java

@@ -1,4 +1,6 @@
 package rocks.zipcode.quiz4.collections.culonary;
 
-public class Curry {
+import sun.security.provider.ConfigFile;
+
+public class Curry implements Spice {
 }

src/main/java/rocks/zipcode/quiz4/collections/culonary/Food.java

@@ -1,20 +1,35 @@
 package rocks.zipcode.quiz4.collections.culonary;
 
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 /**
  * @author leon on 27/12/2018.
  */
 public class Food {
+    private List<Spice> spices = new ArrayList<>();
+
     public List<Spice> getAllSpices() {
-        return null;
+        return this.spices;
     }
 
     public <SpiceType extends Class<? extends Spice>> Map<SpiceType, Integer> getSpiceCount() {
-        return null;
+        Map<SpiceType, Integer> result = new HashMap<>();
+
+        for(Spice s: spices){
+            Integer count = 1;
+            if(result.containsKey((SpiceType) s.getClass())){
+                count = result.get((SpiceType) s.getClass());
+                count++;
+            }
+            result.put((SpiceType) s.getClass(), count);
+        }
+        return result;
     }
 
     public void applySpice(Spice spice) {
+        spices.add(spice);
     }
 }

src/main/java/rocks/zipcode/quiz4/collections/culonary/Ginger.java

@@ -3,5 +3,5 @@
 /**
  * @author leon on 27/12/2018.
  */
-public class Ginger {
+public class Ginger implements Spice {
 }

src/main/java/rocks/zipcode/quiz4/collections/culonary/Pepper.java

@@ -1,7 +1,9 @@
 package rocks.zipcode.quiz4.collections.culonary;
 
+import sun.security.provider.ConfigFile;
+
 /**
  * @author leon on 27/12/2018.
  */
-public class Pepper {
+public class Pepper implements Spice {
 }

src/main/java/rocks/zipcode/quiz4/fundamentals/Calculator.java

@@ -1,35 +1,46 @@
 package rocks.zipcode.quiz4.fundamentals;
 
+import static java.lang.Math.sqrt;
+
 /**
  * @author leon on 21/12/2018.
  */
 public class Calculator {
     public static Double squareRoot(Double value) {
-        return null;
+        return sqrt(value);
     }
 
     public static Double square(Double value) {
-        return null;
+
+        return value * value;
     }
 
     public static Double[] squareRoots(Double... value) {
-        return null;
+
+        Double[] result = new Double[value.length];
+        for (int i = 0; i < value.length ; i++) {
+            result[i] = Math.sqrt(value[i]);
+        }
+        return result;
     }
 
     public static Double[] squares(Double... values) {
-        return null;
+        Double[] result = new Double[values.length];
+        for (int i = 0; i < values.length ; i++) {
+            result[i] = Math.pow(values[i],2);
+        }
+        return result;
     }
 
     public static Double add(Double value1, Double value2) {
-        return null;
+        return value1 + value2;
     }
 
     public static Double subtract(Double value1, Double value2) {
-        return null;
+        return value1 - value2;
     }
 
-
     public static Double divide(Double divisor, Double dividend) {
-        return null;
+        return divisor/dividend;
     }
 }

src/main/java/rocks/zipcode/quiz4/fundamentals/StringUtils.java

@@ -5,30 +5,64 @@
  */
 public class StringUtils {
     public static Character getMiddleCharacter(String string) {
-        return null;
+        return string.charAt(string.length()/2);
     }
 
     public static String capitalizeMiddleCharacter(String str) {
-        return null;
+
+        return str.substring(0,str.length()/2) + getMiddleCharacter(str.toUpperCase()) + str.substring((str.length()/2)+1);
     }
 
     public static String lowerCaseMiddleCharacter(String str) {
-        return null;
+
+        return str.substring(0,str.length()/2) + getMiddleCharacter(str.toLowerCase()) + str.substring((str.length()/2)+1);
     }
 
     public static Boolean isIsogram(String str) {
-        return null;
+
+        char[] element = str.toCharArray();
+        for(int i = 0; i < element.length; i++){
+            for (int j = i+1; j < element.length;j++){
+                if (element[i] == element[j]){
+                    return false;
+                }
+            }
+        }
+        return true;
     }
 
     public static Boolean hasDuplicateConsecutiveCharacters(String str) {
-        return null;
+
+        char[] element = str.toCharArray();
+        for (int i = 0;i < element.length-1;i++){
+            if (element[i] == element[i+1]){
+                return true;
+            }
+        }
+        return false;
     }
 
     public static String removeConsecutiveDuplicateCharacters(String str) {
-        return null;
+
+        for(int i = 0; i < str.length()-1; i++){
+            if (str.charAt(i) == str.charAt(i+1)){
+                str = str.substring(0,i)+ str.substring(i+2);
+            }
+        }
+        return str;
     }
 
     public static String invertCasing(String str) {
-        return null;
+
+        char[] element = str.toCharArray();
+        for(int i = 0; i < element.length; i++) {
+            if(Character.isLowerCase(element[i])) {
+                element[i] = Character.toUpperCase(element[i]);
+            }
+            else {
+                element[i] = Character.toLowerCase(element[i]);
+            }
+        }
+        return String.valueOf(element);
     }
 }

src/main/java/rocks/zipcode/quiz4/objectorientation/account/Account.java

@@ -3,11 +3,14 @@
 /**
  * @author leon on 30/12/2018.
  */
-public class Account extends BankAccount {
+public class Account{
+    Long id;
+
     public Long getId() {
-        return null;
+        return id;
     }
 
     public void setId(Long id) {
+        this.id = id;
     }
 }

src/main/java/rocks/zipcode/quiz4/objectorientation/account/Bank.java

@@ -1,17 +1,26 @@
 package rocks.zipcode.quiz4.objectorientation.account;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * @author leon on 27/12/2018.
  */
 public class Bank {
+
+    private List<BankAccount> accounts = new ArrayList<>();
+
     public BankAccount removeBankAccountByIndex(Integer indexNumber) {
-        return null;
+
+        return accounts.remove(indexNumber.intValue());
     }
 
     public void addBankAccount(BankAccount bankAccount) {
+        accounts.add(bankAccount);
     }
 
     public Boolean containsBankAccount(BankAccount bankAccount) {
-        throw new UnsupportedOperationException("Method not yet implemented");
+        //throw new UnsupportedOperationException("Method not yet implemented");
+        return accounts.contains(bankAccount);
     }
 }

src/main/java/rocks/zipcode/quiz4/objectorientation/account/BankAccount.java

@@ -3,7 +3,27 @@
 /**
  * @author leon on 27/12/2018.
  */
-public class BankAccount {
+public class BankAccount extends Account implements Transactable {
+    Double balance = 0.0;
+
     public void setBalance(Double val) {
+        balance = val;
+    }
+
+    @Override
+    public void deposit(Double amountToIncreaseBy) {
+        if (amountToIncreaseBy < 0) throw new IllegalArgumentException();
+        balance += amountToIncreaseBy;
+    }
+
+    @Override
+    public void withdrawal(Double amountToDecreaseBy) {
+        if (amountToDecreaseBy < 0 || amountToDecreaseBy > balance) throw new IllegalArgumentException();
+        balance -= amountToDecreaseBy;
+    }
+
+    @Override
+    public Double getBalance() {
+        return balance;
     }
 }

src/main/java/rocks/zipcode/quiz4/objectorientation/account/Employee.java

@@ -3,18 +3,59 @@
 /**
  * @author leon on 30/12/2018.
  */
-public class Employee {
+public class Employee implements Worker, Transactable {
+    private BankAccount account;
+    private Double hourlyWage = 35.0;
+    private Double hoursWorked = 0.0;
+
     public Employee() {
+        account = new BankAccount();
     }
 
     public Employee(BankAccount bankAccount) {
+        account = bankAccount;
     }
 
     public BankAccount getBankAccount() {
-        return null;
+        return account;
     }
 
     public void setBankAccount(BankAccount bankAccount) {
+        account = bankAccount;
+    }
+
+    @Override
+    public void deposit(Double amountToIncreaseBy) {
+        account.deposit(amountToIncreaseBy);
+    }
+
+    @Override
+    public void withdrawal(Double amountToDecreaseBy) {
+        account.withdrawal(amountToDecreaseBy);
+    }
+
+    @Override
+    public Double getBalance() {
+        return account.getBalance();
+    }
+
+    @Override
+    public void increaseHoursWorked(Double numberOfHours) {
+        hoursWorked += numberOfHours;
+    }
+
+    @Override
+    public Double getHoursWorked() {
+        return hoursWorked;
+    }
+
+    @Override
+    public Double getHourlyWage() {
+        return hourlyWage;
+    }
 
+    @Override
+    public Double getMoneyEarned() {
+        return hoursWorked * hourlyWage;
     }
 }