Question

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.

Answer 1

Answer:

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<Item> people;

/**

Constructs a LookupTable object.

*/

public LookupTable()

{

people = new ArrayList<Item>();

}

/**

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