438801554

import java.util.*;
class Main
{
   public static void main(String args[])
   {
       Scanner s=new Scanner(System.in);
       Directory dr=new Directory();
       while(true)
       {
           System.out.println("1- Add person details into the telephone book.");
           System.out.println("2- Remove a person from the telephone book.");
           System.out.println("3- Update a telephone number by providing person first name.");
           System.out.println("4- Display the entire telephone book.");
           System.out.println("5- Search a telephone number based on person first name.");
           System.out.println("6- Sort the entire telephone book.");
           System.out.println("7- Exit the program.");
           int choice=s.nextInt();
           switch(choice)
           {
               case 1:
                   System.out.print("Enter first name: ");
                   String first_name=s.next();
                   System.out.print("Enter last name: ");
                   String last_name=s.next();
                   System.out.print("Enter phone number: ");
                   String phone_number=s.next();
                   System.out.print("Enter city: ");
                   String city=s.next();
                   System.out.print("Enter gender: ");
                   char gender=s.next().charAt(0);
                   System.out.print("Enter address: ");
                   String address=s.next();
                   System.out.print("Enter email: ");
                   String email=s.next();
                   Node node=new Node(first_name,last_name,phone_number,city,address,gender,email);
                   dr.insert(node);
                   break;
               case 2:
                   System.out.print("Enter phone number: ");
                   String ph_no=s.next();
                   dr.remove(ph_no);
                   break;
               case 3:
                   System.out.print("Enter first name: ");
                   String f_n=s.next();
                   System.out.print("Enter updated phone number: ");
                   String ph_number=s.next();
                   dr.update(f_n,ph_number);
                   break;
               case 4:
                   dr.display();
                   break;
               case 5:
                   System.out.print("Enter first name to search: ");
                   String f_name=s.next();
                   dr.search(f_name);
                   break;
               case 6:
                   dr.sort();
                   break;
               case 7:
                   return;
               default:
                   System.out.println("Invalid option");
                   break;
           }

       }
   }
}
class Directory
{
   Node head,tail;
   Directory()
   {
       head=null;
       tail=null;
   }
   public void insert(Node node) // method that insert node into list if phone number is new
   {
       Node temp=head;
       while(temp!=null && !temp.phone_number.equals(node.phone_number))
           temp=temp.next;
       if(temp!=null)
       {
           System.out.println("Entered phone number already exists");
           return;
       }
       if(head==null)
       {
           head=node;
           tail=node;
       }
       else
       {
           tail.next=node;
           tail=node;
       }
       System.out.println("Inserted Successfully");
   }
   public void remove(String ph_no)  // method that removes node with given phone number
   {
       Node prev=null;
       Node node=head;
       while(node!=null && !node.phone_number.equals(ph_no))
       {
           prev=node;
           node=node.next;
       }
       if(node==null)
           System.out.println("Phone number not found");
       else if(prev==null)
       {
           head=head.next;
           if(head==null)
               tail=null;
           System.out.println("Deleted Successfully");
       }
       else
       {
           prev.first_name=node.first_name;
           prev.last_name=node.last_name;
           prev.phone_number=node.phone_number;
           prev.city=node.city;
           prev.gender=node.gender;
           prev.address=node.address;
           prev.email=node.email;
           prev.next=node.next;
           System.out.println("Deleted Successfully");
       }
   }
   public void update(String first_name,String phone_number)  // method that updates the phone number of person if exists
   {
       boolean found=false;
       Node node=head;
       while(node!=null)
       {
           if(node.first_name.equals(first_name))
           {
               node.phone_number=phone_number;
               found=true;
           }
           node=node.next;
       }
       if(!found)
           System.out.println("No person found with given first name");
       else
           System.out.println("Updated Successfully");
   }
   public void display() // method that displays data in directory
   {
       if(head==null)
       {
           System.out.println("Empty directory");
           return;
       }
       System.out.println("People are as follows: ");
       Node node=head;
       while(node!=null)
       {
           System.out.println(node.toString());
           node=node.next;
       }
   }
   public void search(String first_name)       // method that searches for person with first name
   {
       Node node=head;
       boolean found=false;
       while(node!=null)
       {
           if(node.first_name.equals(first_name))
           {
               System.out.println(node.toString());
               found=true;
           }
           node=node.next;
       }
       if(!found)
           System.out.println("No person found with given first name");
   }
   public void sort() // sorts data in linked lists according to first name
   {
       Node node1=head;
       while(node1!=null)
       {
           Node node2=node1.next;
           while(node2!=null)
           {
               if(node1.first_name.compareTo(node2.first_name)>0)
               {
                   swap(node1,node2);
               }
               node2=node2.next;
           }
           node1=node1.next;
       }
       System.out.println("Sorted Successfully");
   }
   public void swap(Node n1,Node n2)
   {
       String temp="";

       temp=n1.first_name;
       n1.first_name=n2.first_name;
       n2.first_name=temp;

       temp=n1.last_name;
       n1.last_name=n2.last_name;
       n2.last_name=temp;

       temp=n1.phone_number;
       n1.phone_number=n2.phone_number;
       n2.phone_number=temp;

       temp=n1.city;
       n1.city=n2.city;
       n2.city=temp;

       temp=n1.address;
       n1.address=n2.address;
       n2.address=temp;

       temp=n1.email;
       n1.email=n2.email;
       n2.email=temp;

       char t=n1.gender;
       n1.gender=n2.gender;
       n2.gender=t;
   }
}
// prototype of person details
class Node
{
   String first_name,last_name,phone_number,city,address,email;
   char gender;
   Node next=null;
   Node() { }
   Node(String first_name,String last_name,String phone_number,String city,String address,char gender,String email)
   {
       this.first_name=first_name;
       this.last_name=last_name;
       this.phone_number=phone_number;
       this.city=city;
       this.address=address;
       this.gender=gender;
       this.email=email;
   }
   public String toString()
   {
       return "\nFirst Name: "+this.first_name+"\nLast Name: "+this.last_name+"\nPhone Number: "+this.phone_number+"\nCity: "+this.city+
       "\nAddress: "+this.address+"\nGender: "+this.gender+"\nEmail: "+this.email+"\n";
   }
}