node---Copy.zip_class_node

#include "LinkedList.h" using namespace std; namespace hong_lab5 { //create empty linkedlist LinkedList::LinkedList() { head_ptr = NULL; tail_ptr = NULL; current_ptr = NULL; list_length=0; } //create a linked list with data LinkedList::LinkedList(data_type& data) { head_ptr = new node(data); tail_ptr = head_ptr; current_ptr = tail_ptr; list_length=1; } //destructor LinkedList::~LinkedList() { while(head_ptr != NULL) remove_from_head(); tail_ptr = NULL; } void LinkedList::add_to_head(data_type& data) { //add node for empty list if(list_length==0) { head_ptr = new node(data); tail_ptr = head_ptr; current_ptr = tail_ptr; list_length=1; } //insert node at head else { node* head_insert = new node(data); // new node on the heap head_ptr -> set_previous(head_insert); //set the heads "previous" ptr to the new head and set the next nodes "next" //ptr to the node at the current head head_insert->set_next(head_ptr); head_ptr = head_insert; // set the head ptr from the list to the new node list_length++; // increment to the list head_insert = NULL; } } void LinkedList::add_to_tail(data_type& data) { if(list_length==0) { head_ptr = new node(data); // add node for empty list tail_ptr = head_ptr; list_length=1; } else // insert node at tail { node* tail_insert = new node(data); // new node on the heap tail_ptr ->set_next(tail_insert); tail_insert->set_previous(tail_ptr); tail_ptr = tail_insert; list_length++; tail_insert = NULL; } } void LinkedList::remove_from_head()//do nothing for empty list { if(list_length==0) return; else if(list_length==1) { delete head_ptr; head_ptr = NULL; tail_ptr = NULL; list_length--; return; } else { node* temp_head_ptr = head_ptr; head_ptr = temp_head_ptr->get_next(); delete temp_head_ptr; list_length--; temp_head_ptr=NULL; } } void LinkedList::remove_from_tail() { if(list_length==0) return; else if(list_length==1) { delete head_ptr; head_ptr=NULL; tail_ptr=NULL; list_length--; return; } else { node* temp_tail_ptr = tail_ptr; tail_ptr = temp_tail_ptr->get_previous(); delete temp_tail_ptr; list_length--; temp_tail_ptr=NULL; } } void LinkedList::forward() { current_ptr = current_ptr ->get_next(); } void LinkedList::back() { current_ptr = current_ptr ->get_previous(); } void LinkedList::move_to_head() { current_ptr = head_ptr; } void LinkedList::move_to_tail() { current_ptr = tail_ptr; } LinkedList::data_type LinkedList::get_current() const { return current_ptr->get_data(); } std::size_t LinkedList::size() { return list_length; } }