Add Ellis' code to skeleton

src/main/java/StringManipulation.java

@@ -1,33 +1,134 @@
 public class StringManipulation implements StringManipulationInterface {
 
+    private String string;
+
     @Override
     public String getString() {
-        return null;
+        return string;
     }
 
     @Override
     public void setString(String string) {
+        this.string = string;
     }
 
     @Override
     public int count() {
-        return 0;
+        if (string == null)
+            return 0;
+        if (string.length() == 0)
+            return 0;
+
+        int count = 0;
+        for (int i = 0; i < string.length() - 2; i++) {
+            if (i == 0 && !isSpaceChar(string.charAt(i)))
+                count++;
+            else if (isSpaceChar(string.charAt(i)) && !isSpaceChar(string.charAt(i + 1)))
+                count++;
+        }
+
+        return count;
     }
 
     @Override
     public String removeNthCharacter(int n, boolean maintainSpacing) {
-        return null;
+        if (n <= 0)
+            throw new IllegalArgumentException();
+        if (n > string.length())
+            throw new IndexOutOfBoundsException();
+
+        StringBuilder newStr = new StringBuilder();
+        for (int i = 1; i < string.length() + 1; i++) {
+            if (i % n == 0) {
+                if (maintainSpacing)
+                    newStr.append(' ');
+            } else
+                newStr.append(string.charAt(i - 1));
+        }
+
+        return newStr.toString();
     }
 
     @Override
     public String[] getSubStrings(int startWord, int endWord) {
-        return null;
+        if (count() < endWord)
+            throw new IndexOutOfBoundsException();
+        if (startWord <= 0 || endWord <= 0 || startWord > endWord)
+            throw new IllegalArgumentException();
+
+        String[] words = new String[(endWord - startWord) + 1];
+        int wordIndex = 0;
+
+        StringBuilder sb = new StringBuilder();
+        int wordCount = 0;
+        for (int i = 0; i < string.length() - 1; i++) {
+            // Case where first character is a word
+            if (i == 0 && !isSpaceChar(string.charAt(i))) {
+                wordCount++;
+                if (wordCount == startWord)
+                    sb.append(string.charAt(i));
+
+                // Case where beginning of new word is found
+            } else if (isSpaceChar(string.charAt(i)) && !isSpaceChar(string.charAt(i + 1))) {
+                wordCount++;
+                i++;
+                if (wordCount >= startWord && wordCount <= endWord)
+                    sb.append(string.charAt(i));
+
+                // Case where end of word is found
+            } else if (!isSpaceChar(string.charAt(i)) && isSpaceChar(string.charAt(i + 1))) {
+                if (wordCount >= startWord && wordCount <= endWord) {
+                    sb.append(string.charAt(i));
+                    words[wordIndex++] = sb.toString();
+                    sb = new StringBuilder();
+                }
+
+            } else if (!isSpaceChar(string.charAt(i)) && wordCount >= startWord && wordCount <= endWord) {
+                sb.append(string.charAt(i));
+            }
+        }
+        if (endWord == count()) {
+            sb.append(string.charAt(string.length() - 1));
+            words[wordIndex] = sb.toString();
+        }
+
+        return words;
     }
 
     @Override
-    public String restoreString(int[] indices) {
-        return null;
+    public String restoreString(int[] indices){
+        if (indices.length != string.length())
+            throw new IllegalArgumentException();
+
+        boolean[] indexUsed = new boolean[indices.length];
+        char[] chars = new char[indices.length];
+        for (int i = 0; i < indices.length; i++) {
+            if (indices[i] < 0 || indices[i] > string.length())
+                throw new IndexOutOfBoundsException();
+            if (indexUsed[indices[i]])
+                throw new IllegalArgumentException("Indices must be unique");
+
+            chars[indices[i]] = string.charAt(i);
+            indexUsed[indices[i]] = true;
+        }
+
+        StringBuilder sb = new StringBuilder();
+        for (char c : chars)
+            sb.append(c);
+
+        return sb.toString();
     }
 
 
+    private boolean isSpaceChar(char ch) {
+        // Add any characters considered as a word delimiter
+        char[] spaceChars = {' ', '_', '-', '\t', '\n'};
+
+        for (char c : spaceChars) {
+            if (c == ch)
+                return true;
+        }
+
+        return false;
+    }
 }