DLinkedList.cpp

//DLinkedList.h
//Node.h

//main.cpp
#include <stdio.h>
#include "DLinkedList.h"

int main(){
	DLinkedList *d = new DLinkedList();
	
	for (int i = 0; i <= 10; i++){
		d->add(new Node(i));
	}
	
	for (int i = 0; i < d->m_length; i++){
		d->getAtPrint(i);
	}
	for (int i = 0; i < d->m_length; i++){
		d->getAtPrint(i);
	}
	
	getchar();
	return 0;
}

DLinkedList.h

//DLinkedList.h
#include <stdio.h>
#include "Node.h"

class DLinkedList{
public:
	DLinkedList();
	~DLinkedList();
	Node* FindLast();
	void add(Node *n);
	void remove(int index);
	int getAt(int index);
	void getAtPrint(int index);//デバッグ用関数
public:
	Node *head = NULL;
public:
	int m_length = 0;
};
DLinkedList::DLinkedList(){};
DLinkedList::~DLinkedList(){};
Node *DLinkedList::FindLast(){
	Node *follow = head;
	if (head == NULL){
		return NULL;
	}
	else{
		while (follow->next != nullptr){
			follow = follow->next;
		}
		return follow;
	}
};
void DLinkedList::add(Node *n){
	Node *p_last = FindLast();
	if (head == NULL){
		head = n;
		m_length++;
	}
	else{
		p_last->next = n;
		n->prev = p_last;
		m_length++;
	}
}
void DLinkedList::remove(int index){
	Node *p_follow = head;
	Node *p_prev = nullptr;
	Node *p_next = nullptr;
	if (index > m_length - 1){
		return;
	}
	else{
		if (head == NULL)return;
		for (int i = 0; i < index; i++){
			if (i==index-1)p_prev = p_follow;
			p_follow = p_follow->next;
		}
		p_next = p_follow->next;
		//head
		if (p_prev == nullptr){
			if (p_next == nullptr){
				head = NULL;
			}
			else{
				head = p_next;
				head->prev = nullptr;
				delete p_follow;
			}		
		}
		//last
		else if (p_follow->next == nullptr){
			p_prev->next = nullptr;
			delete p_follow;
		}
		else{
			p_prev->next = p_next;
			p_next->prev = p_prev;
			delete p_follow;
		}
		m_length--;
	}
}
int DLinkedList::getAt(int index){
	Node *p_follow = head;
	if (index > m_length - 1){
		return NULL;
	}
	for (int i = 0; i < index; i++){
		p_follow = p_follow->next;
	}
	return p_follow->value;
}
void DLinkedList::getAtPrint(int index){
	Node *p_follow = head;
	if (index > m_length - 1){
		return;
	}
	for (int i = 0; i < index; i++){
		p_follow = p_follow->next;
	}
	if (p_follow == nullptr)return;
	if (p_follow->next == nullptr)
		printf("getAt(%d): here:%p prev:%p next:%p\n", index, p_follow, p_follow->prev, NULL);
	else if (p_follow->prev == nullptr)	
		printf("getAt(%d): here:%p prev:%p next:%p\n", index, p_follow, NULL, p_follow->next);
	else
		printf("getAt(%d): here:%p prev:%p next:%p\n", index, p_follow, p_follow->prev, p_follow->next);
}

Node.h

//Node.h
//int
class Node{
public:
	Node();
	Node(int val);
	~Node();
	void setValue(int val);
	int getValue();
public:
	int value;
	Node *next;
	Node *prev;
};
//実装部
Node::Node(){
	value = NULL;
	next = nullptr;
	prev = nullptr;
};
Node::Node(int val){
	value = val;
	next = nullptr;
	prev = nullptr;
};
Node::~Node(){};
void Node::setValue(int val){
	value = val;
}
int Node::getValue(){
	return value;
}