How do I "return that data at specific position if present"

Question

For this lab, I cannot for the life of me figure out what to do here. This is part of the prompt for my assignment:

//return the data at specific position if it is present
E getData(int index)

I assume that I am to display a value tied to a node using indexes. However, my professor has us doing this in an odd way so my linked list exists, but I don't know how to call to it.

The code below is what makes the list appear in the console:

public static void main(String[] args) {
    LinkedList<Integer> myList = new LinkedList<Integer>();
    //Add Data
    myList.addData(4);
    myList.addData(2);
    myList.addData(1);
    myList.printList();
    //Add Data At End
    myList.addDataAtEnd(5);
    System.out.println();
    myList.printList();
    //Add Data At Specific Spot
    myList.addDataSpecificSpot(3);
    System.out.println();
    myList.printList();

the methods are below:

printList

public void printList() {
    Node<E> current = head;
    while(current != null) {
        System.out.print(current.data + " --> ");
        current = current.next;
    }
}

addData

public void addData(E data) {
    Node<E> newNode = new Node<E>(data);
    newNode.next = head;
    head = newNode;
}

addDataAtEnd

public void addDataAtEnd(E data) {
    Node<E> newNode = new Node<E>(data);
    Node<E> current = head;
    while(current.next != null) {
        current = current.next;
    }
    newNode.next = null;
    current.next = newNode;
}

addDataSpecificSpot

public void addDataSpecificSpot(E data) {
    Node<E> newNode = new Node<E>(data);
    Node<E> current = head;
    while(current.next.next.next != null) {
        current = current.next;
    }
    newNode.next = current.next;
    current.next = newNode;
}

So, after all that happens, the console outputs this:

1 --> 2 --> 4
1 --> 2 --> 4 --> 5
1 --> 2 --> 3 --> 4 --> 5

How would I implement the getData method to find a value within a certain index? I just am at a loss for what to do.

Assume 0 is the index of the list head. Then, index of 1 is 1 hop through `Node.next`. So for index of `N`, you should do `N` hops. And that's that. — M. Prokhorov, Oct 28 '21 at 18:24
Does this answer your question? [How can I get an element from linked list with given index in java?](https://stackoverflow.com/questions/56344563/how-can-i-get-an-element-from-linked-list-with-given-index-in-java) — trincot, Oct 29 '21 at 06:44

score 0 · Answer 1 · answered Oct 29 '21 at 06:40

You can have the counter and iterate through the List.

Check counter with specified location whose data you want to find out, If counter is less than the specified number then list does not have that much data. This way you can implement the logic.

    public void getDataFromSpecifiedLocation(E data, int location) {
      Node<E> newNode = new Node<E>(data);
      Node<E> current = head;
      int counter=0;
      while(current.next.next.next != null && counter<location) {
        current = current.next;
        counter++;
        if(counter==location)
         break;  
      }
   
      System.out.println("Node at location "+ location+" is "+ current);
}

So like this you can implement the logic.

How do I "return that data at specific position if present"

1 Answers1