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.

See explaination

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 people;

/**

Constructs a LookupTable object.

*/

public LookupTable ()

{

people = new ArrayList ();

}

/**

Reads key/value pairs.

atparam 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.

atparam k the key to find

atreturn 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.

atparam v the value to find

atreturn 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

Note: Replace all the "at" with at symbol