反转链接列表中的错误

Question

Can a pointer be altered when we are altering another pointer pointing to same address

Code for reversing Linked List

 Node Reverse(Node node) {
    Node prev = null;
    Node current = node;
    Node next = null;
   Node n = null;
    while (current != null) {
         n = current;
         next = current.next;       //this works
         n.next = prev;
    //  next = current.next;      //this does not
        prev = n;
     current = next;
    }
    node = prev;
    return node;
}

Doubt: How can Node n affect the node current. When i write n.next , current getting affected, but why?

Answer 1

@Gaurav Anand

Yes, it does affect the value of current because Node current and n has the same address and any changes made to either of the variable will be reflected in both as value at address will change.

In your code:
When next = current.next is placed after n.next = prev it doesn't works because you have changed the value of n.next which is same as current.next to NULL (prev = NULL) as the Node current and n has same address.

So, if you use place next = current.next after n.next = prev then current = NULL and loop will stop iterating.

Answer 2

This is because n points to current only. 2 references are pointing to the same object and thus when you change n.next, changes are reflected in current.next as well