#pragma once #include <iostream> using namespace std; template <typename T> class LinkedList { private: int size; ListNode<T>* head; public: //Constructor LinkedList() { size = 0; head = nullptr; } //Copy Constructor //Destructor //Copy assignment (operator overload) //Methods void prepend(T item) {} void append(T item) {} };
The Correct Answer and Explanation is:
Here is the corrected and more complete version of the LinkedList class including the missing components like the copy constructor, destructor, and copy assignment operator. It also defines the ListNode class which is necessary for the LinkedList to function properly.
cppCopyEdit#pragma once
#include <iostream>
using namespace std;
template <typename T>
class ListNode {
public:
T data;
ListNode<T>* next;
ListNode(T value) : data(value), next(nullptr) {}
};
template <typename T>
class LinkedList {
private:
int size;
ListNode<T>* head;
void clear() {
while (head != nullptr) {
ListNode<T>* temp = head;
head = head->next;
delete temp;
}
size = 0;
}
void copyFrom(const LinkedList<T>& other) {
if (other.head == nullptr) {
head = nullptr;
size = 0;
return;
}
head = new ListNode<T>(other.head->data);
ListNode<T>* current = head;
ListNode<T>* otherCurrent = other.head->next;
while (otherCurrent != nullptr) {
current->next = new ListNode<T>(otherCurrent->data);
current = current->next;
otherCurrent = otherCurrent->next;
}
size = other.size;
}
public:
// Constructor
LinkedList() : size(0), head(nullptr) {}
// Copy Constructor
LinkedList(const LinkedList<T>& other) {
copyFrom(other);
}
// Destructor
~LinkedList() {
clear();
}
// Copy Assignment Operator
LinkedList<T>& operator=(const LinkedList<T>& other) {
if (this != &other) {
clear();
copyFrom(other);
}
return *this;
}
// Prepend Method
void prepend(T item) {
ListNode<T>* newNode = new ListNode<T>(item);
newNode->next = head;
head = newNode;
size++;
}
// Append Method
void append(T item) {
ListNode<T>* newNode = new ListNode<T>(item);
if (head == nullptr) {
head = newNode;
} else {
ListNode<T>* temp = head;
while (temp->next != nullptr) {
temp = temp->next;
}
temp->next = newNode;
}
size++;
}
// Optional: Display contents for testing
void display() const {
ListNode<T>* temp = head;
while (temp != nullptr) {
cout << temp->data << " -> ";
temp = temp->next;
}
cout << "nullptr" << endl;
}
};
Explanation (300 words):
The LinkedList class is a template-based singly linked list implementation. Each node in the list is represented by the ListNode class, containing a data value and a pointer to the next node. The linked list tracks its size and the pointer to the head node.
The constructor initializes an empty list with size set to 0 and head as nullptr. The copy constructor creates a deep copy of another list by iterating through its nodes and replicating their data. This avoids shared references between different list objects. The destructor ensures that all dynamically allocated memory is released by calling the clear function, which deletes each node in the list.
The copy assignment operator allows one list to be assigned the contents of another. It checks for self-assignment and clears the current list before copying the elements from the source list.
The prepend method inserts a new node at the beginning by making the new node’s next pointer refer to the current head and then updating the head to this new node. The size is incremented.
The append method adds a node at the end. If the list is empty, it sets the new node as the head. Otherwise, it traverses to the last node and updates its next pointer.
The display method helps in visually checking the contents of the list. Proper memory management and separation of duties in helper methods ensure correctness and efficiency.
