still not finished

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

@@ -1,22 +1,54 @@
 package rocks.zipcode.quiz4.arrays;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
 /**
  * @author leon on 01/01/2019.
  */
 public class ArrayUtils {
     public static String getMiddleElement(String[] values) {
-        return null;
+        int middleIndex = (int) (values.length / 2);
+        String middle = values[middleIndex];
+
+        return middle;
+
     }
 
     public static String[] removeMiddleElement(String[] values) {
-        return null;
+        String middle = ArrayUtils.getMiddleElement(values);
+        List<String> al = new ArrayList<String>(Arrays.asList(values));
+
+        List<String> newList = al.stream().filter(x -> !x.equals(middle)).collect(Collectors.toList());
+        String[] result = new String[newList.size()];
+        newList.toArray(result);
+        return result;
+
     }
 
     public static String getLastElement(String[] values) {
-        return null;
+        String result = values[values.length - 1];
+
+        return result;
     }
 
     public static String[] removeLastElement(String[] values) {
-        return null;
+       // String last = getLastElement(values);
+
+
+        ArrayList<String> al = new ArrayList<>();
+        for(int i=0 ;i < values.length; i++){
+            al.add(values[i]);
+        }
+        al.remove(al.size()-1);
+        String[] result = new String[al.size()];
+        al.toArray(result);
+        return result;
+//        List<String> newList = al.stream().filter(x -> !x.equals(last)).collect(Collectors.toList());
+//        String[] result = new String[newList.size()];
+//        newList.toArray(result);
+//        return result;
     }
 }

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

@@ -1,12 +1,24 @@
 package rocks.zipcode.quiz4.collections;
 
+import java.util.HashMap;
 import java.util.Map;
 
 public class WordCounter {
+    String[]strings;
     public WordCounter(String... strings) {
+        this.strings = strings;
     }
 
     public Map<String, Integer> getWordCountMap() {
-        return null;
+        Map<String,Integer>map = new HashMap<>();
+        for (int i = 0; i < strings.length ; i++) {
+            if(!map.containsKey(strings[i])){
+                map.put(strings[i],1);
+            }
+            else{
+                map.put(strings[i],map.get(strings[i])+1);
+            }
+        }
+        return map;
     }
 }

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

@@ -1,4 +1,16 @@
 package rocks.zipcode.quiz4.collections.culonary;
 
-public class Curry {
+public class Curry implements Spice{
+    private static Curry INSTANCE = new Curry();
+    private String name;
+
+    static Curry getInstance(){
+
+        return INSTANCE;
+    }
+
+    public String getName (){
+        return name;
+    }
+
 }

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

@@ -1,20 +1,31 @@
 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 {
+public class Food implements Spice{
+    List<Spice>spiceList = new ArrayList<>();
+
     public List<Spice> getAllSpices() {
-        return null;
+        return this.spiceList;
     }
 
     public <SpiceType extends Class<? extends Spice>> Map<SpiceType, Integer> getSpiceCount() {
-        return null;
+        Map<Class<? extends Spice>, Integer> map = new HashMap<>();
+        for (Spice spice : spiceList)
+            if (!map.containsKey(spice)) {
+                map.put(spice.getClass(), spiceList.size());
+            } else {
+                return null;
+            }
+       return (Map<SpiceType, Integer>) map;
     }
-
     public void applySpice(Spice spice) {
+        spiceList.add(spice);
     }
 }

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

@@ -3,5 +3,10 @@
 /**
  * @author leon on 27/12/2018.
  */
-public class Ginger {
+public class Ginger implements Spice{
+    private static Ginger INSTANCE = new Ginger();
+
+    static Ginger getInstance(){
+        return INSTANCE;
+    }
 }

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

@@ -3,5 +3,10 @@
 /**
  * @author leon on 27/12/2018.
  */
-public class Pepper {
+public class Pepper implements Spice{
+    private static Pepper INSTANCE = new Pepper();
+
+    static Pepper getInstance(){
+        return INSTANCE;
+    }
 }

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

@@ -1,35 +1,58 @@
 package rocks.zipcode.quiz4.fundamentals;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 /**
  * @author leon on 21/12/2018.
  */
 public class Calculator {
     public static Double squareRoot(Double value) {
-        return null;
+        return (Double) Math.sqrt(value);
     }
 
     public static Double square(Double value) {
-        return null;
+        return value * value;
+
     }
 
     public static Double[] squareRoots(Double... value) {
-        return null;
+
+        List<Double> al =new ArrayList(Arrays.asList(value));
+        List<Double> newList = new ArrayList<>();
+        for(Double x : al){
+            newList.add(Math.sqrt(x));
+        }
+        Double[] result = new Double[newList.size()];
+        newList.toArray(result);
+        return result;
+
     }
 
     public static Double[] squares(Double... values) {
-        return null;
+        List<Double> al =new ArrayList(Arrays.asList(values));
+        List<Double> newList = new ArrayList<>();
+        for(Double x : al){
+            newList.add(x*x);
+        }
+        Double[] result = new Double[newList.size()];
+        newList.toArray(result);
+        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

@@ -1,34 +1,104 @@
 package rocks.zipcode.quiz4.fundamentals;
 
+import java.util.Arrays;
+
 /**
  * @author leon on 21/12/2018.
  */
 public class StringUtils {
     public static Character getMiddleCharacter(String string) {
-        return null;
+
+        char[] chars = string.toCharArray();
+        int middleIndex = chars.length / 2;
+        Character m = chars[middleIndex];
+        return m;
     }
 
     public static String capitalizeMiddleCharacter(String str) {
-        return null;
+        int middleIndex = str.length() / 2;
+        String result = "";
+        for (int i = 0; i < str.length(); i++) {
+            if (i != middleIndex) {
+                result = result + str.charAt(i);
+            }
+            if (i == middleIndex) {
+                result = result + Character.toUpperCase(str.charAt(i));
+            }
+
+
+        }
+        return result;
+
     }
 
     public static String lowerCaseMiddleCharacter(String str) {
-        return null;
+        int middleIndex = str.length() / 2;
+        String result = "";
+        for (int i = 0; i < str.length(); i++) {
+            if (i != middleIndex) {
+                result = result + str.charAt(i);
+            }
+            if (i == middleIndex) {
+                result = result + Character.toLowerCase(str.charAt(i));
+            }
+
+
+        }
+
+        return result;
+
     }
 
     public static Boolean isIsogram(String str) {
-        return null;
+        int len = str.length();
+
+        char arr[] = str.toCharArray();
+
+        Arrays.sort(arr);
+        for (int i = 0; i < len - 1; i++) {
+            if (arr[i] == arr[i + 1])
+                return false;
+        }
+        return true;
+
+
     }
 
     public static Boolean hasDuplicateConsecutiveCharacters(String str) {
-        return null;
+        int len = str.length();
+
+        char arr[] = str.toCharArray();
+        for (int i = 0; i < len - 1; i++) {
+            if (arr[i] == arr[i + 1])
+                return true;
+        }
+        return false;
+
     }
 
     public static String removeConsecutiveDuplicateCharacters(String str) {
-        return null;
+        StringBuilder sb = new StringBuilder();
+        for(int i = 0; i< str.length()-1; i++){
+            if(str.charAt(i) == str.charAt(i+1)){
+                i++;
+            }
+            else {
+                sb.append(str.charAt(i));
+            }
+        }
+        sb.append(str.charAt(str.length()-1));
+        return sb.toString();
+
     }
 
     public static String invertCasing(String str) {
-        return null;
+        String result = "";
+        for (int i = 0; i < str.length(); i++) {
+            if (str.charAt(i) == Character.toUpperCase(str.charAt(i))) {
+                result = result + Character.toLowerCase(str.charAt(i));
+            } else
+                result = result + Character.toUpperCase(str.charAt(i));
+        }
+        return result;
     }
 }

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

@@ -3,11 +3,16 @@
 /**
  * @author leon on 30/12/2018.
  */
-public class Account extends BankAccount {
+public class Account  {
+    private Long id;
+
+
+
     public Long getId() {
-        return null;
+        return this.id;
     }
 
     public void setId(Long id) {
+        this.id = id;
     }
 }