IT1230809

Implementation of Double-Ended List

class Link {

public int iData;

public double dData:

public Link next;



public Link(int id,double dd) {

iData = id;

dData=dd;

}

public void displayLink(){

System.out.print("{"+iData+","dData+"}");

}

}



class FirstLastList {

private Link first;

private Link last;

public FirstLastList() {

first = null;

last = null;

}

public boolean isEmpty() {

return (first == null);

}

public void insertFirst(int id,double dd) {

Link newLink = new Link(id,dd);



if (isEmpty ())

last = newLink;

newLink.next = first;

first = newLink;

}

public void insertLast(int id,double dd) {

Link newLink = new Link(id,dd);



if (isEmpty())

first = newLink;

else

last.next = newLink;

last = newLink;

}

public Link deleteFirst(int id,double dd) {



int temp = first.iData;



if (first.next == null)

last = null;

first = first.next;

return temp;

}
public Link deleteLast(int id, double dd){

int temp=last.iData;

if(last.next==null)

first=null;
last=last.next;
return temp;
}
public void displayList(){

System.out.print("List(first-->Last);");

Link current=first;



while(current!=null){

current.displayLink();

current=current.next;

}

}

System.out.println(" ");

}

}

public class FirstLastApp{

public static void main(String[] args) {



FirstLastList theList = new FirstLastList();



theList.insertFirst(22,2.99);

theList.insertFirst(44,4.99);

theList.insertFirst(66,6.99);

theList.insertLast(11,1.99);

theList.insertLast(33,3.99);

theList.insertLast(55,5.99);



System.out.println(theList);

theList.deleteFirst();

theList.deleteFirst();

System.out.println(theList);

}

}