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Thread: Help with linked list problem

  1. #1
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    Default Help with linked list problem

    This is my code and after printing the result i get is 0 for each item
    import java.util.Scanner; 
     
    class Node {
        public int data;
        public Node next;
     
        //Link constructor
        public Node(int d1) {
    	    this.data=data;	    
        }
     
        //Print Link data
        public void printNode() {
    	    System.out.print(data);
        }
    }
     
    class LinkList {
        private Node first;
     
        //LinkList constructor
        public LinkList() {
    	    first=null;
        }
     
        //Returns true if list is empty
        public boolean isEmpty() {
    	    return first == null;
        }
     
        //Inserts a new Link at the first of the list
        public void insert(int d1) {
    	    Node newNode = new Node(d1);
    	    newNode.next = first;
    	    first = newNode;
        }
     
        //Deletes the link at the first of the list
        public Node delete() {
    	    Node temp = first;
    	    first = first.next;
    	    return temp;
        }
     
        //Prints list data
        public void printList() {
    	    Node current = first;
    	    System.out.print("List: ");
    	    while(current != null) {
    		    current.printNode();
    		    current = current.next;
    	    }
    	    System.out.println("");
        }
    }  
     
    class LinkListTest {
        public static void main(String[] args) {
            Scanner scan = new Scanner(System.in);
    	    LinkList list = new LinkList();
                int data=0;
     
                System.out.print("Please enter a succession of integers. Enter 0 to end ");
     
     
                while(data!=999){
                    data=scan.nextInt();
                    list.insert(data);
                }
     
    	    list.printList();
     
    	    while(!list.isEmpty()) {
    		    Node deletedLink = list.delete();
    		    System.out.print("deleted: ");
    		    deletedLink.printNode();
    		    System.out.println("");
    	    }
    	    list.printList();
        }
    }


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Help with linked list problem

    Where does the code assign a value to data?
    What does the constructor do with the arg that is passed to it in d1?
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Help with linked list problem

    what does this.data=data mean in your constructor? you only have one data member, public int data, defined so your constructor isn't assigning anything... your boolean method in the LinkList class i think would be better to have a conditional statement for first == null and then have it explicitly return true

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Help with linked list problem

    I think this is fine:
    return first == null;
    If you don't understand my answer, don't ignore it, ask a question.

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