half way?

src/main/java/rocks/zipcode/quiz5/fundamentals/Calculator.java

@@ -18,14 +18,18 @@ public class Calculator {
 
     public static Double[] squareRoots(Double... value) {
         Double[] roots = new Double[value.length];
-        for (int i = 0; i < value.length; i++){
-//            roots[i] = Math.sqrt(value)[i]
+        for (int i=0; i< value.length; i++){
+            roots[i] = Math.sqrt(value[i]);
         }
-        return null;
+        return roots;
     }
 
     public static Double[] squares(Double... values) {
-        return null;
+        Double[] sqs = new Double[values.length];
+        for (int i=0; i< values.length; i++){
+            sqs[i] = values[i] * values[i];
+        }
+        return sqs;
     }
 
     public static Double add(Double value1, Double value2) {

src/main/java/rocks/zipcode/quiz5/fundamentals/StringUtils.java

@@ -5,7 +5,7 @@ package rocks.zipcode.quiz5.fundamentals;
  */
 public class StringUtils {
     public static Character getMiddleCharacter(String string) {
-        return null;
+        return string.charAt(string.length()/2);
     }
 
     public static String capitalizeMiddleCharacter(String str) {
@@ -17,15 +17,35 @@ public class StringUtils {
     }
 
     public static Boolean isIsogram(String str) {
-        return null;
+        for(int i = 0; i < str.length(); i++){
+            for (int j = i+1; j < str.length(); j++){
+                if (str.charAt(i) == str.charAt(j)){
+                    return false;
+                }
+            }
+        }
+
+        return true;
     }
 
     public static Boolean hasDuplicateConsecutiveCharacters(String str) {
-        return null;
+        for(int i = 0; i < str.length()-1; i++){
+            if(str.charAt(i) == str.charAt(i +1)){
+                return true;
+            }
+        }
+        return false;
     }
 
     public static String removeConsecutiveDuplicateCharacters(String str) {
-        return null;
+        String nString = new String();
+        int index = 0;
+        for (int i = 0; i < str.length(); i++){
+            char c = str.charAt(i);
+                nString += c;
+        }
+
+        return nString;
     }
 
     public static String invertCasing(String str) {

src/main/java/rocks/zipcode/quiz5/objectorientation/account/Employee.java

@@ -3,7 +3,7 @@ package rocks.zipcode.quiz5.objectorientation.account;
 /**
  * @author leon on 30/12/2018.
  */
-public class Employee {
+public class Employee implements Worker{
     public Employee() {
     }
 
@@ -17,4 +17,24 @@ public class Employee {
     public void setBankAccount(BankAccount bankAccount) {
 
     }
+
+    @Override
+    public void increaseHoursWorked(Double numberOfHours) {
+
+    }
+
+    @Override
+    public Double getHoursWorked() {
+        return null;
+    }
+
+    @Override
+    public Double getHourlyWage() {
+        return null;
+    }
+
+    @Override
+    public Double getMoneyEarned() {
+        return null;
+    }
 }