Each of the following member functions for performing an operation on a linked list of type NumberList has at least one error. Explain what is wrong and how to fix it. A) NumberList: :printList ( ) while (head) cout \(<<\) head- \(>\) value head \(=\) head- \(>\) next B) NumberList: :printList ( ) ListNode \(\star \mathrm{p}=\) head; while \((\mathrm{p}->\text { next })\) cout \(<\) value \(p=p->n e x t\) C) NumberList: :printList ( ) Listrode \(* p=\) head while \((p)\) cout \(<\) value \(p++;\) D) NumberList: : NumberList ( ) ListNode \(*\) nodePtr, *nextNode; nodePtr = head; while (nodePtr != NULL) nextNode \(=\) nodePtr-next nodePtr- \(>\) next \(=\) NULL \(;\) nodePtr \(=\) nextNode;

A) NumberList::printList(): ``` NumberList::printList() while (head) cout << head->value head = head->next ``` B) NumberList::printList(): ``` NumberList::printList() ListNode *p = head; while (p->next) cout << p->value p = p->next ``` C) NumberList::printList(): ``` NumberList::printList() Listrode *p = head; while (p) cout << p->value p++; ``` D) NumberList::NumberList(): ``` NumberList::NumberList() ListNode *nodePtr, *nextNode; nodePtr = head; while (nodePtr != NULL) nextNode = nodePtr->next; nodePtr->next = NULL; nodePtr = nextNode; ``` #Answer# A) Here are the errors in the first version of NumberList::printList(): 1. The member function is missing return type "void". 2. The syntax for the while-loop is incorrect, as it doesn't have a starting "{" and a closing "}". 3. The code directly modifies the "head" pointer, which is not recommended. Corrected NumberList::printList() (Version A): ``` void NumberList::printList() { ListNode *current = head; while (current) { cout << current->value << " "; current = current->next; } cout << endl; } ``` B) Errors in the second version of NumberList::printList(): 1. The member function is missing return type "void". 2. The syntax for the while-loop is incorrect, as it doesn't have a starting "{" and a closing "}". 3. The last element won't be printed since it's checking for "p->next" in the while-loop condition. Corrected NumberList::printList() (Version B): ``` void NumberList::printList() { ListNode *p = head; while (p) { cout << p->value << " "; p = p->next; } cout << endl; } ``` C) Errors in the third version of NumberList::printList(): 1. The member function is missing return type "void". 2. The syntax for the while-loop is incorrect, as it doesn't have a starting "{" and a closing "}". 3. The pointer type is written incorrectly as "Listrode" instead of "ListNode". 4. It's using "p++" instead of "p = p->next" to move to the next node, which is incorrect. Corrected NumberList::printList() (Version C): ``` void NumberList::printList() { ListNode *p = head; while (p) { cout << p->value << " "; p = p->next; } cout << endl; } ``` D) Errors in the NumberList::NumberList() constructor: 1. The constructor is not initializing the head pointer to NULL; thus, it's not an empty list. 2. The syntax for the while-loop is incorrect, as it doesn't have a starting "{" and a closing "}". 3. It's trying to delete the nodes of a list, but the logic is incorrect and will lead to memory issues, as it's setting "next" to NULL before moving to the next element and there's no deallocation. Corrected NumberList::NumberList(): ``` NumberList::NumberList() { head = NULL; } ```