public void reversePointer() throws Exception {
if (this.size == 0)
throw new Exception(">>> list is empty => reverseData >>>");
Node prev = this.head;
Node curr = prev.next;
int count = 1;
while (curr != null) {
Node ahead = curr.next;
curr.next = prev;
System.out.println(count);
count++;
prev = curr;
curr = ahead;
}
Node t = this.head;
this.head = this.tail;
this.tail = t;
}@javadsalgo123,
change the while loop condition to curr.next!=null.
Also, share the complete code if your query is not resolved.
reverse pointer function is not working
Your logic was right. You missed a line in the code. You had to include the line this.tail.next = null; at last.
not working , still can’t figure out why ?
@javadsalgo123,
In the code I shared.
For the input:
5
1 2 3 4 5
Output should be: (when printing data)
before reversing
1=>2=>3=>4=>5=>end
after reversing
5=>4=>3=>2=>1=>end
Input
5
1 2 3 4 5
Output (when printing nodes. The output will vary from system to system):
before reversing
Main$Node@6aaa5eb0=>Main$Node@3498ed=>Main$Node@1a407d53=>Main$Node@3d8c7aca=>Main$Node@5ebec15=>end
after reversing
Main$Node@5ebec15=>Main$Node@3d8c7aca=>Main$Node@1a407d53=>Main$Node@3498ed=>Main$Node@6aaa5eb0=>end
I am not able to display the linked list again , i don’t know why?
Comment the print in the while loop in reversepointer method. Put 2 displays method, one before reversepointer and one after reversepointer. Call the reversepointer method again. And share a screenshot of that.
I am executing the same code I sent to you. Also, please share a screenshot of the method from which you are calling the reversePointer.@javadsalgo123,
In the reverse pointer function:
Use
while (curr != null) {
Instead of:
while (curr.next != null) {
I made a mistake myself when I told you edit that. It was correct. 
The code should work now.
@javadsalgo123,
the output looks correct, except that the tail element is not being displayed. Can you send me your display function please?
public void display() {
Node temp = this.head;
System.out.println("head "+this.head.data);
System.out.println("tail "+this.tail.data);
System.out.println(“size “+this.size);
while (temp.next != null) {
System.out.print(temp.data + “=>”);
temp = temp.next;
}
System.out.println(“end”);
System.out.println(”============================”);
}
@javadsalgo123,
Don’t use
while (temp.next != null) {
just put:
while(temp!=null)
In the display function
@javadsalgo123,
Because if the next in a node is null, we can still print its data but if the node is null, that’s when we have to exit.
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