Given the algorithm for deleting nodes from an ordered double linked list (or a

Question

Given the algorithm for deleting nodes from an ordered double linked list (or a portion of the algorithm) in real code, be able to fill in the blanks. List Node *MyDoubleLinkedList::Delete (int Key) { //Assume ListNode is a structure and contains the variable int key; // and ListNode *prev, *next; //Assume the function returns a pointer to the node if it successfully removes the node // or NULL if the node was not found ListNode *temp = head; //Search for node to delete while ((___________) && (___________)) { _____________; //Advance to next node if (________________) //Check for node to delete not found return Null; else if (______________) //Check for deleting head of the list { _____________; //Remove the head of the list if(head ! = NULL) //Make sure head is not now NULL _______________; Set head's prev pointer return temp;// Return the node removed } else //Delete node elsewhere in the list { __________________; //Move pointer of node before temp if(temp rightarrow next ! = NULL) ______________; return temp; } return NULL; //This line will never be reached but it keeps the compiler from complaining

Explanation / Answer

ListNode *MyDoublyLinkedList::Delete(int Key)
{
   // Assume ListNode is a structure and contains the variable int key;
   // and ListNode *prev, *next;
   // Assume the function returns a pointer to the node if it successfully removes the node
   // or NULL if the node was not found.
   ListNode *temp = head;   //Initializes the temp pointer to the start of the list.
   //Search for node to delete.
   while((temp->next != NULL) && (temp->key <= newNode->key))   //Till you either reach the end of list, or the position to insert.
        temp = temp->next;   //Keep moving forward.
    if(temp->key > Key)    //Check for node to delete not found.
        return NULL;   //Confirm the node is not in the List.
    else if(head->key == Key)           //Check for deleting head of the list.  
    {
       head = head->next;   //Bypasses the first node.
       if(head != NULL)   //Make sure head is not now NULL.
           head->prev = NULL;   //Set head's prev pointer to NULL.
       return temp;   //Return the node removed.  
    }
    else   //Delete node elsewhere in the list.
    {
       temp->prev->next = temp->next;   //Move pointer of node before temp.
       if(temp->next != NULL)   //If the removed node is not the last node.
           temp->next->prev = temp->prev;   //Set the next pointer -> prev point to the previous node.
       return temp;  
    }
    return NULL;   //This line will never be reached but it keeps the compiler from complaining.
}

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