Create a reverse LinkedList in C from a given LinkedList

0 votes

I'm having some problems making a linkedlist from a provided linkedlist in reverse order.

I have a background in java and have just begun working with C++.

Could you go at my code and let me know what's wrong? 

I anticipate that all I'm doing is changing the cursor, not producing anything new.

//this is a method of linkedlist class, it creates a reverse linkedlist
//and prints it

void LinkedList::reversedLinkedList()
{
    Node* revHead;

    //check if the regular list is empty
    if(head == NULL)
       return;

    //else start reversing
    Node* current = head;
    while(current != NULL)
    {
        //check if it's the first one being added
        if(revHead == NULL)
           revHead = current;

        else
        {
            //just insert at the beginning
            Node* tempHead = revHead;
            current->next = tempHead;
            revHead = current;
        }
        current = current->next;

     }//end while

     //now print it
     cout << "Reversed LinkedList: " << endl;

     Node* temp = revHead;
     while(temp != NULL)
     {
         cout << temp->firstName << endl;
         cout << temp->lastName << endl;
         cout << endl;

         temp = temp->next;
      }

}//end method
Aug 3 in C++ by Nicholas
• 5,020 points
12 views

1 answer to this question.

0 votes

A simpler solution is to just let the current node point to the previous node while going through your linked list, saving the previous and next nodes as you go.

void LinkedList::reversedLinkedList()
{
    if(head == NULL) return;

    Node *prev = NULL, *current = NULL, *next = NULL;
    current = head;
    while(current != NULL){
        next = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }
    // now let the head point at the last node (prev)
    head = prev;
}
answered Aug 5 by Damon
• 4,960 points

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