Shelan's reverse words

lib/reverse_words.rb

@@ -1,4 +1,46 @@
 # A method to reverse each word in a sentence, in place.
+
+# time complexity is O(n) b/c it goes through the loop n times based on the length of word inputted.
+
+# space complexity is O(1) b/c the storage does not increase in size based on the input.
+
+def string_reverse(my_string, beginning, ending)
+  front_index = beginning
+  back_index = ending
+
+  while front_index < back_index
+    front_value = my_string[front_index]
+    back_value = my_string[back_index]
+
+    my_string[front_index] = back_value
+    my_string[back_index] = front_value
+
+    front_index += 1
+    back_index -= 1
+  end
+end
+###
+
 def reverse_words(my_words)
-  raise NotImplementedError
+  return if my_words == nil
+
+  i = 0
+  length = my_words.length
+
+  while i < length
+    while my_words[i] == ' ' && i < length
+      i += 1
+    end
+
+    beginning = i
+
+    while my_words[i] != ' ' && i < length
+      i += 1
+    end
+
+    ending = i - 1
+
+    string_reverse(my_words, beginning, ending)
+  end
+  return my_words
 end