Merge pull request #85 from nhu313/patch-1

Update README.md

README.md

 
 ### Part I:
 
-Create a PhoneBook class that holds names and phone numbers in sorted order. You can use an associative data type (one which stores items as keys paired with values).
-
-Your PhoneBook class should have a lookup() method which allows you to look up a person's phone number based on their name. PhoneBook should also have methods to add and remove entries, or to list all names or all entries (names an phone numbers).
+Create a PhoneBook class that holds names and phone numbers. You can use an associative data type (one which stores items as keys paired with values). (Hint: You should use a sorted map).
+
+Your PhoneBook class should have the following method
+  * lookup(String name) -  allows you to look up a person's phone number based on their name
+  * add(String name, String phoneNumber) - add entry
+  * remove(String name) - remove entry
+  * display() - list all entries (names an phone numbers) in alphabetical order
+
+    ```java
+      PhoneBook phoneBook = new PhoneBook();
+      phoneBook.add("Zebra", "111-222-333");
+      phoneBook.add("Dog", "222-444-4444");
+      phoneBook.display(); 
+      
+      /*
+       Calling display this should print out the entries like this
+       Dog 222-444-4444
+       Zebra 111-222-333
+      */
+      
+    ```
 
 ### Part II: