1. Write a telephone lookup program. Read a data set of 1, 000 names and telephone numbers from a file that contains the numbers in random order. Handle lookups by name and also reverse lookups by phone number. Use a binary search for both lookups.

Kindly note that, you're to replace "at" with shift 2 as the text editor can't take the symbol

Explanation:

PhoneLookup.java

import java.io.FileReader;

import java.io.IOException;

import java.util.Scanner;

public class PhoneLookup

{

  public static void main(String[] args) throws IOException

  {

     Scanner in = new Scanner(System.in);

     System.out.println("Enter the name of the phonebook file: ");

     String fileName = in.nextLine();

     LookupTable table = new LookupTable();

     FileReader reader = new FileReader(fileName);

     table.read(new Scanner(reader));

     boolean more = true;

     while (more)

     {

        System.out.println("Lookup N)ame, P)hone number, Q)uit?");

        String cmd = in.nextLine();

        if (cmd.equalsIgnoreCase("Q"))

           more = false;

        else if (cmd.equalsIgnoreCase("N"))

        {

           System.out.println("Enter name:");

           String n = in.nextLine();

           System.out.println("Phone number: " + table.lookup(n));

        }

        else if (cmd.equalsIgnoreCase("P"))

        {

           System.out.println("Enter phone number:");

           String n = in.nextLine();

           System.out.println("Name: " + table.reverseLookup(n));

        }

     }

  }

}

LookupTable.java

import java.util.ArrayList;

import java.util.Collections;

import java.util.Scanner;

/**

  A table for lookups and reverse lookups

*/

public class LookupTable

{

  private ArrayList<Item> people;

  /**

     Constructs a LookupTable object.

  */

  public LookupTable()

  {

      people = new ArrayList<Item>();

  }

  /**

     Reads key/value pairs.

     "at"param in the scanner for reading the input

  */

  public void read(Scanner in)

  {

     while(in.hasNext()){

         String name = in.nextLine();

         String number = in.nextLine();

         people.add(new Item(name, number));

     }

  }

  /**

     Looks up an item in the table.

     "at"param k the key to find

     "at"return the value with the given key, or null if no

     such item was found.

  */

  public String lookup(String k)

  {

     String output = null;

     for(Item item: people){

         if(k.equals(item.getName())){

             output = item.getNumber();

         }

     }

     return output;

  }

  /**

     Looks up an item in the table.

     "at"param v the value to find

     "at"return the key with the given value, or null if no

     such item was found.

  */

  public String reverseLookup(String v)

  {

      String output = null;

         for(Item item: people){

             if(v.equals(item.getNumber())){

                 output = item.getName();

             }

         }

         return output;

  }

}

Item.java

public class Item {

  private String name, number;

  public Item(String aName, String aNumber){

      name = aName;

      number = aNumber;

  }

  public String getName(){

      return name;

  }

  public String getNumber(){

      return number;

  }

}

input.txt

Abbott, Amy

408-924-1669

Abeyta, Ric

408-924-2185

Abrams, Arthur

408-924-6120

Abriam-Yago, Kathy

408-924-3159

Accardo, Dan

408-924-2236

Acevedo, Elvira

408-924-5200

Acevedo, Gloria

408-924-6556

Achtenhagen, Stephen

408-924-3522

Kindly check the attached output image below.

yes, but you must first make sure that you'll be able to make your turn or you can crash into other vehicles.

answerhard disks;