import java.io.BufferedReader;
import java.io.IOException;
import java.io.FileReader;
import java.io.FileNotFoundException;
 
public class TelephoneLookup
{
   public static void main(String[] args)
   {  // read data from a file
      FileReader reader = null;
 
      // prompt user for filename
      ConsoleReader console = new ConsoleReader(System.in);
      System.out.print("Enter the name of the phonebook file: ");
      String fileName = console.readLine();
 
      LookupTable names = new LookupTable(1000);
      LookupTable numbers = new LookupTable(1000);
 
      //open the input file
      try
      {  reader = new FileReader(fileName);
         names.read(new BufferedReader(reader));
         numbers.read(new BufferedReader(reader));
      }
      catch(FileNotFoundException e)
      {
		  System.out.println("Cannot find input file ");
		  System.exit(1);
	  }
      catch (IOException e)
      {  System.out.println("Cannot open input file ");
         System.exit(2);
      }
 
 
 
      boolean more = true;
      while (more)
      {  System.out.println("Lookup N)ame, P)hone number, Q)uit?");
         String cmd = console.readLine().toUpperCase();
         if (cmd.equals("Q")) more = false;
         else if (cmd.equals("N"))
         {  System.out.println("Enter name:");
            String n = console.readLine();
            //call the lookup method in the LookupTable class
            System.out.println("Phone number: " + names.lookup(n));
		 }
         else if (cmd.equals("P"))
         {  System.out.println("Enter phone number:");
            String n = console.readLine();
            //call the lookup method in the LookupTable class
            System.out.println("Name: " + numbers.lookup(n));
         }
      }
   }
}
 

import java.io.BufferedReader;
import java.io.IOException;
import java.io.FileReader;
import java.io.FileNotFoundException;
 
public class LookupTable
{
   private Item[] items;
   int itemCount;
 
 
   public LookupTable(int n)
   {  items = new Item[n];
      itemCount = 0;
   }
 
   public void read(BufferedReader in) throws IOException
   {  boolean more = true;
      while (more && itemCount < items.length)
      {  String k = in.readLine();
         String v = null;
         if (k != null) v = in.readLine();
         if (v != null)
         {  items[itemCount] = new Item(k, v);
            itemCount++;
         }
         else more = false;
      }
      // must sort before you can call binarySearch
      mergeSort(items, 0, itemCount - 1);
   }
 
   // THERE IS CODE IN HERE YOU MUST ADD TO MAKE THIS WORK; PERHAPS YOU WANT TWO DIFFERENT
   // lookup METHODS??
 
 
   public String lookup(String k)
   {  int pos = binarySearch(items, 0, itemCount - 1, k);
      if (pos < 0)
         return "Not found";
      else
         return items[pos].getValue();
   }
 
   public static void merge(Item[] a, int from, int mid, int to)
   {  //YOU WRITE THIS CODE
   }
 
 
   public static void mergeSort(Item[] a, int from, int to)
   {   //YOU WRITE THIS CODE
   }
 
   public static int binarySearch(Item[] v, int from, int to, String a)
   {   //YOU WRITE THIS CODE
   }
 
 
}

public class Item
{  private String key;
   private String value;
 
   public Item(String k, String v)
   {  key = k;
      value = v;
   }
 
   public String getKey()
   {  return key;
   }
   public void setKey(String newKey)
   {
	  key = newKey;
   }
 
   public String getValue()
   {  return value;
   }
 
   public void setValue(String newValue)
   {
	   value = newValue;
   }
 
}