Question

PLEASE WRITE IN JAVA AND ADD COMMENTS TO EXPLAIN

write a class NameCard.java which has

•Data fields: name (String), age(int), company(String)

•Methods:

•Public String getName();

•Public int getAge();

•Public String getCom();

•Public void setName(String n);

•Public void setAge(int a);

•Public void setCom(String c);

•toString(): \\ can be used to output information on this name card

2, write a class DoublyNameCardList.java, which is a doubly linked list and each node of the list a name card.

In the DoublyNameCardList.java:

•Data field:

•Reference data type: head, which always references the first node of the doubly linked list

•Reference data type: tail, which aways references the last node of the doubly linked list

•int count, which is used to record the number of name cards in the list

•Method:

•public DoublyNameCardList(); // A constructor which can initialize the list:

•public void addEnd(NameCard x); // A method that allows you to place a value at the end of the list

•public void addHead(NameCard x); // A method that allows you to place a value at the begin of the list

•public void add(int index, NameCard x); //A method that allows you to place a name card after the given location

• public NameCard get(int index); //A method that allows you to retrieve a name card from a given location

•public int size(); // A method that allows you to return the number of elements that is currently in the list

•public void delete (index n); //A method that will remove a name card at the given index

•Public boolean exist(NameCard n); // test if there has a name card in the list which has same content with n

Now, write a driver program (the class with the public static void main(String[] args) method) name test.java to test the data structure you just created:

•   Fill in the list with 5 name card objects

•   print the list on the screen two times:

•From head to tail

•From tail to head

•    Call the method in the DoublyNameCardList class one by one, each method you called,

•Print out a message to show what have you done

•print out all the name cards in the list

Answer 1

==========Test.java=============

public class Test {

   public static void main(String[] args) {
       System.out.print("ok");
       DoublyNameCardList list = new DoublyNameCardList();
        list.addHead(new NameCard("loknath",28,"oracle"));
        list.addEnd(new NameCard("loknath",2,"zen"));
        list.addEnd(new NameCard("loknath",7,"zen"));
        list.addEnd(new NameCard("loknath",27,"zen"));
        list.addEnd(new NameCard("loknath",27,"zen"));  
        list.addEnd(new NameCard("loknath",27,"zen"));
        list.add(2, new NameCard("ok", 88,"test"));
        System.out.println(list);
   }
}

======================= NameCard.java ==================
public class NameCard {
   private String name;
   private int age;
   private String company;
   private NameCard next;
   private NameCard pre;
   public NameCard(){
      
   }
   public NameCard(String n,int a,String c){
       name = n;
       age = a;
       company = c;
       next=null;
       pre=null;
   }
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public String getCompany() {
       return company;
   }
   public void setCompany(String company) {
       this.company = company;
   }
   public int getAge() {
       return age;
   }
   public void setAge(int age) {
       this.age = age;
   }
  
   @Override
   public String toString(){
       return " (" + name+", "+age+", "+company+" ) ";
   }
   public NameCard getNext() {
       return next;
   }
   public void setNext(NameCard next) {
       this.next = next;
   }
   public NameCard getPre() {
       return pre;
   }
   public void setPre(NameCard pre) {
       this.pre = pre;
   }
}

=======================DoublyNameCardList.java============

public class DoublyNameCardList {
   NameCard head;
   NameCard tail;
   int count;
  
   public DoublyNameCardList(){
       head = new NameCard();
       tail = new NameCard();
       tail.setPre(head);
       head.setNext(tail);
       count=0;
   }
   public void addHead(NameCard x){
       x.setNext(head.getNext());
       x.getNext().setPre(x);
       head = x;
   }
   public void addEnd(NameCard x){
       x.setPre(tail.getPre());
       x.setNext(tail);
       x.getPre().setNext(x);
       tail.setPre(x);
   }
   public void add(int index, NameCard x){
       // fix the position
       if (index < 0) {
           index = 0;
       }
       if (index > count) {
           index = count;
       }

       // if the list is empty, make it be the only element
       if (head == null) {
           head = x;
           tail = head;
       }
       // if adding at the front of the list...
       else if (index == 0) {
           x.setNext(head);
           head = x;
       }
       // else find the correct position and insert
       else {
           NameCard temp = head;
           for (int i=1; i<index; i+=1) {
               temp = temp.getNext();
           }
                  
           x.setNext(x.getNext());
           x.setPre(temp);
           x.getNext().setPre(x);
           temp.setNext(x);
       }
       // the list is now one value longer
       count += 1;
   }
   public void delete (int index) {
       // fix position
       if (index < 0) {
           index = 0;
       }
      
       if (index >= count) {
           index = count-1;
       }
      
       // if nothing in the list, do nothing
       if (head == null)
           return;
      
       // if removing the head element...
       if (index == 0) {
           head = head.getNext();
           if (head == null)
               tail = null;
       }
       // else advance to the correct position and remove
       else {
           NameCard temp = head;
           for (int i=1; i<index; i+=1) {
               temp = temp.getNext();
           }
           temp.getNext().setPre(temp.getPre());
           temp.getPre().setNext(temp.getNext());
       }
       // reduce the length of the list
       count -= 1;
   }
   public int size(){
       return count;
   }
  
   public NameCard get(int index){
       int i=0;
       NameCard tempCard=head;
       while(i<index){
           if(tempCard==null){
               System.out.println("Index out of bond! Unable to get");
               return null;
           }
           tempCard = tempCard.getNext();  
           i++;
       }
       return tempCard;
   }
   public String toString(){
       NameCard temp = head;
       while(temp!=null){
           System.out.println(temp);
           temp =temp.getNext();
       }
       return "";
   }
}