pre-merge commit

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

@@ -1,35 +1,46 @@
 package rocks.zipcode.quiz5.fundamentals;
+import org.decimal4j.util.DoubleRounder;
+
+import java.lang.Math;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
  * @author leon on 21/12/2018.
  */
 public class Calculator {
     public static Double squareRoot(Double value) {
-        return null;
+        return DoubleRounder.round(Math.sqrt(value),2);
     }
 
     public static Double square(Double value) {
-        return null;
+        return DoubleRounder.round(value*value,2);
     }
 
     public static Double[] squareRoots(Double... value) {
-        return null;
+        List<Double> roots = new ArrayList<>();
+        for(Double num : value)
+            roots.add(squareRoot(num));
+        return roots.toArray(new Double[0]);
     }
 
     public static Double[] squares(Double... values) {
-        return null;
+        List<Double> roots = new ArrayList<>();
+        for(Double num : values)
+            roots.add(square(num));
+        return roots.toArray(new Double[0]);
     }
 
     public static Double add(Double value1, Double value2) {
-        return null;
+        return DoubleRounder.round(value1 + value2, 2);
     }
 
     public static Double subtract(Double value1, Double value2) {
-        return null;
+        return DoubleRounder.round(value1 + value2, 2);
     }
 
 
     public static Double divide(Double divisor, Double dividend) {
-        return null;
+        return DoubleRounder.round(divisor / dividend, 2);
     }
 }

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

@@ -1,34 +1,60 @@
 package rocks.zipcode.quiz5.fundamentals;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * @author leon on 21/12/2018.
  */
 public class StringUtils {
-    public static Character getMiddleCharacter(String string) {
-        return null;
+    public static Character getMiddleCharacter(String string){
+        return string.charAt(string.length()/2);
     }
 
     public static String capitalizeMiddleCharacter(String str) {
-        return null;
+        StringBuilder sb = new StringBuilder(str);
+        sb.setCharAt(str.length() / 2, Character.toUpperCase(getMiddleCharacter(str)));
+        return sb.toString();
     }
 
     public static String lowerCaseMiddleCharacter(String str) {
-        return null;
+        StringBuilder sb = new StringBuilder(str);
+        sb.setCharAt(str.length() / 2, Character.toLowerCase(getMiddleCharacter(str)));
+        return sb.toString();
     }
 
     public static Boolean isIsogram(String str) {
-        return null;
+        String[] arr = str.split("");
+        Set<String> set = new HashSet<>(Arrays.asList(arr));
+        return (str.length() == set.size());
     }
 
     public static Boolean hasDuplicateConsecutiveCharacters(String str) {
-        return null;
+        char[] charArr = str.toCharArray();
+        for(int i = 0; i < charArr.length - 1; i++)
+            if(charArr[i]==charArr[i+1])
+                return true;
+        return false;
     }
 
     public static String removeConsecutiveDuplicateCharacters(String str) {
-        return null;
+        Set<Integer> set = new HashSet<>();
+        char[] array = str.toCharArray();
+        StringBuilder sb = new StringBuilder(str);
+        for(int i = 1; i < array.length; i++)
+            if(array[i-1] == array[i]) {
+                set.add(i - 1);
+                set.add(i);
+            }
+        int numDeleted = 0;
+        for(Integer num : set)
+            sb.deleteCharAt(num - numDeleted++);
+        return sb.toString();
     }
 
     public static String invertCasing(String str) {
-        return null;
+        return org.apache.commons.lang3.StringUtils.swapCase(str);
     }
 }