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PhoneBook.java

@@ -1,7 +1,47 @@
  
+import java.util.List;
+import java.util.ArrayList;
+import java.util.TreeMap;
+import java.util.Set;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Collections;
 
 /**
  * Created by leon on 1/23/18.
  */
 public class PhoneBook {
+    TreeMap<String,String> phoneMap = new TreeMap<String, String>();
+    String name; 
+    String phoneNumber;
+    public PhoneBook(String name, String phoneNumber){
+    //Constructor
+    this.name = name;
+    this.phoneNumber = phoneNumber;
+    }
+    
+    public void add(String name, String phoneNumber){
+        phoneMap.put(name, phoneNumber);
+    }
+    
+    public void remove(String name){
+     phoneMap.remove(name); 
+    }
+    
+    public String lookup(String name){
+     return phoneMap.get(name); 
+    }
+    
+    public String reverseLookup(String phoneNumber){
+      return phoneMap.get(phoneNumber);
+    }
+    
+    public String display(){
+        String resultString = "";
+        for(String e : phoneMap.keySet()){
+            String v = phoneMap.get(e);
+            resultString = resultString + e + " -> " + v + "\n";
+    }
+    return resultString;
+}
 }