双向链表基础操作C++实现

template <class T> struct Node
{
T val;
Node<T>* next;
Node<T>* prev;
Node(T nVal)
{
val = nVal;
next =prev= nullptr;
}
Node(void){}
};

#include "Node.h"
#include <iostream>

using namespace std;

template <class> class LinkList
{
int size;
public:
Node<T>* head;
Node<T>* tail;
LinkList(void)
{
head = tail = nullptr;
size = 0;
}
~LinkList(void){ Clear(); }

void AddBack(T val)
{
Node<T>* pNode = new Node<T>(val);
if (head == nullptr)
{
head = tail = pNode;
}
else
{
tail->next = pNode;
pNode->prev = tail;
tail = pNode;
}
size++;
}

void AddFront(T val)
{
Node<T>* pNode = new Node<T>(val);
if (head == nullptr)
{
head = tail = pNode;
}
else
{
head->prev = pNode;
pNode->next = head;
head = pNode;
}
size++;
}

bool insertAt(int pos, T val)
{
Node<T>* pNode = nullptr;
if (pos<0 || pos>size)
{
cout << "out of range" << endl;
return false;
}
pNode = new Node<T>(val);
if (pos == 0)
AddFront(val);
else if (pos = size - 1)
AddBack(val);
else
{
Node<T>* prevNode = GetPointerAt(pos - 1);
pNode->next = prevNode->next;
pNode->prev = prevNode;
preNode->next->prev = pNode;
prevNode->next = pNode;
}
size++;
return true;
}

bool RemoveAt(int pos)
{
Node<T>* pNode = nullptr;
if (size == 0)
{
cout << "list is empty" << endl;
return false;
}
if (pos<0 || pos>size - 1)
{
cout << "out of range" << endl;
return false;
}
if (size == 1)
Clear();
else
{
if (pos == 0)
{
pNode = head;
head = head->next;
head->prev = nullptr;
delete pNode;
}
else
{
Node<T>* prevNode = GetPointerAt(pos - 1);
pNode = prevNode->next;
prevNode->next = pNode->next;
pNode->next->prev = prevNode;
delete pNode;
if (pos == size - 1)
tail = prevNode;
}

}
}

bool RemoveBack()
{
return RemoveAt(size - 1);
}

bool RemoveFront()
{
return RemoveAt(0);
}

int Find(T val)
{
int index = 0;
Node<T>* ip = head;
while (ip != nullptr)
{
if (ip->val == val)
return index;
ip = ip->next;
index++;
}
return -1;
}

bool IsEmpty()
{
return size == 0 ? true : false;
}

void Clear()
{
while (head != nullptr)
{
Node<T>* tmp = head->next;
delete head;
head = tmp;
}
tail = nullptr;
size = 0;
}

private:
Node<T>* GetPointerAt(int pos)
{
Node<T>* pNode = nullptr;
if (pos<0 || pos>size - 1)
cout << "out of range" << endl;
else
{
pNode = head;
for (int i = 1; i <= pos; i++)
pNode = pNode->next;
}
return pNode;
}
};