Question

In Java

You are going to create a PhoneRecord class containing the following properties:

• firstName - which is a String
• lastName - which is a String
• number - which should also be a String

the properties will be public, and it should have two constructors: one which simply constructs the string and another that accepts values for first name, lastname and phone number.

You should also create a class called Phone Book. It should contain an array of Phone Records and a count of howmany records there actually are. The number of records is passed to it by the contructor call, i.e.,:
PhoneBook pb = new PhoneBook(3);
will construct a phone book that can contain up to 3 listings.

The methods are:

• readRecord() - which reads in a new phone record.
• toString(int i) - which returns a string containing record #i
• writeRecord(int i) - which writes record #i.
• writeBook() - which writes the entire phone book.

Write another class that uses the phone book, obtaining its size as a command line argument. Read in several records, write one or two of them and write the whole phone book.

Answer 1

PHONE RECODE CLASS

//Phone record Class
public class PhoneRecord {

   //Variables in Phone record class
   public String firstName;
   public String lastName;
   public String number;
  
   //Constructor which simply constructs the string
   public PhoneRecord()
   {
       this.firstName=null;
       this.lastName=null;
       this.number=null;
   }
  
  
   //Constructor accepts values for first name, last name and phone number.
   public PhoneRecord(String firstName,String lastName,String number)
   {
       this.firstName=firstName;
       this.lastName=lastName;
       this.number=number;
      
   }
}

PHONEBOOK CLASS

import java.util.Scanner;

//Phone Book Class
public class PhoneBook {
  
   static Scanner sc=new Scanner(System.in);
   PhoneRecord array[];//contains the array of phone records
   public int count=0;//to count of how many records there actually are
   int total_records; // total records that array can contain
  
  
   //Constructor that takes how many records should store maximum
   public PhoneBook(int total_records)
   {
       this.total_records=total_records;
       array=new PhoneRecord[total_records];//initializing array with max records
   }
  
   //Method to read the record
   public void readRecord()
   {
       if(count==total_records) //if Book is full
       {
           System.out.println("Phone Book is Full ");
           return;
       }
      
       else //if Book not full take the phone records and store in array
       {
           System.out.println("- - - Reading Phone Record - - - ");
           System.out.print("First name: ");
           String firstName=sc.nextLine();
           System.out.print("Last name: ");
           String lastName=sc.nextLine();
           System.out.print("Number: ");
           String number=sc.nextLine();
           array[count]=new PhoneRecord(firstName,lastName,number);
           count++;
          
       }
   }
  
   //Method to return Phone records details at specific index number
   public String toString(int i)
   {
       //ASSUMING RECORD NUMBERS START FROM 1
       if(i>=count)//if try to take non existing record
       {
           return null;
       }
       //if record found of specific record then return
       return array[i-1].firstName+" "+array[i-1].lastName+" "+array[i-1].number;
   }
  
   //Method to write phone records details at specific index number
   public void writeRecord(int i)
   {
       //ASSUMING RECORD NUMBERS START FROM 1
       if(i>=count)//if try to take non existing record
       {
           System.out.println("No record found..");
       }
       //if record found at specific record then print records
       System.out.println("Phone record "+i);
       PhoneRecord record=array[i-1];
       System.out.println(record.firstName+" "+record.lastName+" "+record.number);
   }

  
   //Method to Write the complete phoneBook
   public void writeBook()
   {
      
       if(count==0) //if no records in book
       {
           System.out.println("No Records in PhoneBook ");
          
       }
       else//if records in phone book
       {
           System.out.println("Phone Book: ");
           for(int i=0;i<count;i++)
           {
               PhoneRecord record=array[i];
               System.out.println(record.firstName+" "+record.lastName+" "+record.number);
           }
       }
       System.out.println();
   }

}

PHONEBOOKUTIL CLASS

import java.util.Scanner;

public class PhoneBookUtil {

   public static void main(String[] args) {
      
       Scanner sc=new Scanner(System.in);
       System.out.print("Size of Phone Book: ");
       int size=sc.nextInt();//obtaining its size as a command line argument
       PhoneBook phonebook=new PhoneBook(size);//Passing maximum size of phone book
       phonebook.readRecord();//read the record
       phonebook.readRecord();//read the record
       phonebook.readRecord();//read the record
       phonebook.readRecord();//read the record
       phonebook.writeBook();//write complete phone book
       phonebook.writeRecord(3);//write record 3
       System.out.println("Record 1 :\n"+phonebook.toString(1));//return and print the record1
       sc.close();
      

   }

}

OUTPUT OF ABOVE CODE:

Size of Phone Book: 4
- - - Reading Phone Record - - -
First name: Sudeepthi
Last name: Maruvada
Number: 97584637638
- - - Reading Phone Record - - -
First name: Kowlutla
Last name: Mangali
Number: 948794748
- - - Reading Phone Record - - -
First name: Roopasri
Last name: Mangali
Number: 9489584947
- - - Reading Phone Record - - -
First name: HinduSri
Last name: Mangali
Number: 9574836733
Phone Book:
Sudeepthi Maruvada 97584637638
Kowlutla Mangali 948794748
Roopasri Mangali 9489584947
HinduSri Mangali 9574836733

Phone record 3
Roopasri Mangali 9489584947
Record 1 :
Sudeepthi Maruvada 97584637638