Reverse Linked List

[Susheellattala]

please find what I'am doing wrong in this code.
3 5 7 9 null is my Linked List
output using this code 3 null
public Node reverseNode(Node head){
Node prevNode = null ;
Node currNode = head ;
Node tempNode = currNode ;
while (currNode != null) {
currNode.next = prevNode ;
prevNode = currNode ;
currNode = tempNode.next ;
tempNode = currNode ;
}
head = prevNode;
return head ;
}

 

[WhiteCube]

This is a guess, since I've read only one Java book, and have written zero Java programs.

Before the while loop, tempNode and currNode have the same value. They are references to the same node.

so, inside the loop,

currNode.next = prevNode;

is also changing the value of tempNode.next

Which is a problem.

 

[WhiteCube]

Perhaps I should clarify,

tempNode = currNode ;

does not copy the node, tempNode now refers to the same node as currNode.

To get the program to work,

tempNext = currNode.next;

would be a better approach.

 

[Infinityhost]

"I need to..." "Starting point is.." "Expected output is.."