# lab 9 new assignment

*label*Other

*timer*Asked: Nov 11th, 2016

**Question description**

We have seen in class how to model and implement a queue dynamically using a Linked List in a composition relation.

Implement the class Queue that uses Linked List as an inheritance relation.

__Note:__ You have as attachment the code of the Linked List and Queue using Linked List as composition. You just need to modify it.

#ifndef LINKEDLIST_H #define LINKEDLIST_H #include <stdexcept> using namespace std; template<typename T> class Node { public: T element; // Element contained in the node Node<T> *next; // Pointer to the next node Node() // No-arg constructor { next = NULL; } Node(T element) // Constructor { this->element = element; next = NULL; } }; template<typename T> class LinkedList { public: LinkedList(); void addFirst(T element); void addLast(T element); T getFirst(); T getLast(); T removeFirst() throw (runtime_error); T removeLast(); void add(T element); void add(int index, T element); void clear(); bool contains(T element); T get(int index); int indexOf(T element); bool isEmpty(); int lastIndexOf(T element); bool remove(T element); int getSize(); T remove(int index); T set(int index, T element); private: Node<T> *head, *tail; int size; }; template<typename T> LinkedList<T>::LinkedList() { head = tail = NULL; size = 0; } template<typename T> void LinkedList<T>::addFirst(T element) { Node<T> *newNode = new Node<T>(element); newNode->next = head; head = newNode; size++; if (tail == NULL) tail = head; } template<typename T> void LinkedList<T>::addLast(T element) { if (tail == NULL) { head = tail = new Node<T>(element); } else { tail->next = new Node<T>(element); tail = tail->next; } size++; } template<typename T> T LinkedList<T>::getFirst() { if (size == 0) throw runtime_error("Index out of range"); else return head->element; } template<typename T> T LinkedList<T>::getLast() { if (size == 0) throw runtime_error("Index out of range"); else return tail->element; } template<typename T> T LinkedList<T>::removeFirst() throw (runtime_error) { if (size == 0) throw runtime_error("No elements in the list"); else { Node<T> *temp = head; head = head->next; size--; T element = temp->element; delete temp; return element; } } template<typename T> T LinkedList<T>::removeLast() { if (size == 0) throw runtime_error("No elements in the list"); else if (size == 1) { Node<T> *temp = head; head = tail = NULL; size = 0; T element = temp->element; delete temp; return element; } else { Node<T> *current = head; for (int i = 0; i < size - 2; i++) current = current->next; Node<T> *temp = tail; tail = current; tail->next = NULL; size--; T element = temp->element; delete temp; return element; } } template<typename T> void LinkedList<T>::add(T element) { addLast(element); } template<typename T> void LinkedList<T>::add(int index, T element) { if (index == 0) addFirst(element); else if (index >= size) addLast(element); else { Node<T> *current = head; for (int i = 1; i < index; i++) current = current->next; Node<T> *temp = current->next; current->next = new Node<T>(element); (current->next)->next = temp; size++; } } template<typename T> void clear() { while (head != NULL) { Node<T> *temp = head; delete temp; head = head->next; } tail = NULL; } template<typename T> T LinkedList<T>::get(int index) { if (index < 0 || index > size - 1) throw runtime_error("Index out of range"); Node<T> *current = head; for (int i = 0; i < index; i++) current = current->next; return current->element; } template<typename T> int LinkedList<T>::indexOf(T element) { // Implement it in this exercise Node<T> *current = head; for (int i = 0; i < size; i++) { if (current->element == element) return i; current = current->next; } return -1; } template<typename T> bool LinkedList<T>::isEmpty() { return head == NULL; } template<typename T> int LinkedList<T>::getSize() { return size; } template<typename T> T LinkedList<T>::remove(int index) { if (index < 0 || index >= size) throw runtime_error("Index out of range"); else if (index == 0) return removeFirst(); else if (index == size - 1) return removeLast(); else { Node<T> *previous = head; for (int i = 1; i < index; i++) { previous = previous->next; } Node<T> *current = previous->next; previous->next = current->next; size--; T element = current->element; delete current; return element; } } template<typename T> bool LinkedList<T>::remove(T element) { Node<T> *previous = head; Node<T> *current; if (head != NULL) { if (element == head->element) { head = head->next; size--; return true; } else { current = head->next; } } else return false; for (int i = 0; i < size - 1; i++) { if (element == current->element) { previous->next = current->next; // Remove the current element size--; return true; } else { previous = current; current = current->next; } } return false; } template<typename T> int LinkedList<T>::lastIndexOf(T element) { int lastIndex = -1; Node<T> *current = head; for (int i = 0; i < size; i++) { if (current->element == element) lastIndex = i; current = current->next; } return lastIndex; } template<typename T> bool LinkedList<T>::contains(T element) { // Implement it in this exercise Node<T> *current = head; for (int i = 0; i < size; i++) { if (current->element == element) return true; current = current->next; } return false; } template<typename T> T LinkedList<T>::set(int index, T element) { if (index < 0 || index >= size) throw runtime_error("Index out of range"); Node<T> *current = head; for (int i = 0; i < index; i++) { current = current->next; } T oldElement = current->element; current->element = element; return oldElement; } #endif