This is my method to swap two adjacent elements by adjusting only the links (and

Question

This is my method to swap two adjacent elements by adjusting only the links (and not the data) using a single linked list. But when I run the test program it is printing the list without the swap. Any advice or help as to what i am doing wrong would be appreciated.

Notes: beforep is an input parameter that represents the node before the two adjacent nodes that are to be swapped.

public class Problem1Swapping {

    public static void swapWithNext(Node beforeP) {
        Node p; //First Node to be swapped
        Node afterP;//Second Node to be swapped

        p = beforeP.next;
        afterP = p.next;

        p.next = afterP.next;
        beforeP.next = afterP;
        afterP.next = p;
    }

}

//Provided Node class to use for problem 1
    public class Node {

        public Object data;
        public Node next;

        public Node(Object data, Node next) {
            this.data = data;
            this.next = next;
        }
      
        @Override
        public String toString(){
            return this.data + "";         
        }
    }

public class Problem1SwappingTester {
  
    public static void main(String args[]){
      
        Node node1 = new Node(25, null);
        Node node2 = new Node(35, node1);
        Node node3 = new Node(46, node2);
        Node node4 = new Node(57, node3);
        Node node5 = new Node(68, node4);

        LinkedList list1 = new LinkedList();
        list1.add(node5);
        list1.add(node4);
        list1.add(node3);
        list1.add(node2);
        list1.add(node1);
      
        System.out.println(list1);
        Problem1Swapping.swapWithNext(node3);
        System.out.println(list1);
    }   
}

OUTPUT:

run:
[68, 57, 46, 35, 25]
[68, 57, 46, 35, 25]
BUILD SUCCESSFUL (total time: 0 seconds)

Explanation / Answer

--> Problem1Swapping.swapWithNext(node3); // Here you are just sending node3.. So you cant access the list inside the Problem1Swapping.swapWithNext() function.

--> You are printing the same list twice, and thats why you got the same output.

--> Send 2 parameters to Problem1Swapping.swapWithNext(). The parameters are list and node3.

--> Iterate the list till you find node3, after that do the swap. Your swap code is correct.

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