双向循环链表-----C++
#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<assert.h>
using namespace std;
typedef int DataType;
// define double-circular-linked-list-node
struct ListNode
{
DataType _data;
ListNode* _prev;
ListNode* _next;
};
class DCListNode//double-circular-linked-list-node的简称
{
public:
ListNode* NewNode(const DataType& x)
{
ListNode* cur = new ListNode;
cur->_data = x;
cur->_next = NULL;
cur->_prev = NULL;
return cur;
}
void Print()
{
if (_phead == NULL)
{
;//因为函数最后有cout<<"null"<<endl;
}
else if (_phead->_next == _phead)
{
cout << _phead->_data << "-";
}
else
{
ListNode* cur = _phead;
while (cur->_next != _phead)
{
cout << cur->_data << "-";
cur = cur->_next;
}
cout << cur->_data << "-";//因为此时cur指向最后一个节点
}
cout << "null" << endl;
}
void PushBack(DataType x)
{
ListNode* cur = NewNode(x);
if (_phead == NULL)
{
_phead = cur;
cur->_next = _phead;
cur->_prev = _phead;
}
else if (_phead->_next == _phead)
{
_phead->_next = cur;
cur->_prev = _phead;
cur->_next = _phead;
_phead->_prev = cur;
}
else
{
ListNode* tem = _phead->_prev;
tem->_next = cur;
cur->_prev = tem;
cur->_next = _phead;
_phead->_prev = cur;
}
}
void PopBack()
{
if (_phead == NULL)
{
return;
}
else if (_phead->_next == _phead)
{
_phead = NULL;
}
else if (_phead->_next->_next == _phead)
{
_phead->_next = _phead;
_phead->_prev = _phead;
}
else
{
ListNode* tem = _phead->_prev->_prev;
tem->_next = _phead;
_phead->_prev = tem;
}
}
ListNode* Find(DataType x)
{
ListNode* cur = _phead;
if (_phead == NULL)
{
return NULL;
}
else if (_phead->_next == _phead)
{
if (_phead->_data == x)
{
return _phead;
}
else
{
return NULL;
}
}
else
{
if (cur->_prev->_data == x)
{
return cur->_prev;//因为后面的循环不能遍历到最后一个节点
}
while (cur->_next != _phead)
{
if (cur->_data == x)
{
return cur;
}
else
{
cur = cur->_next;
}
}
return NULL;
}
}
void Insert(ListNode* pos,const DataType& x)
{
assert(pos);
ListNode* cur = NewNode(x);
if (pos->_next != _phead)
{
ListNode* tem = pos->_next;
pos->_next = cur;
cur->_prev = pos;
cur->_next = tem;
tem->_prev = cur;
}
else
{
pos->_next = cur;
cur->_prev = pos;
cur->_next = _phead;
_phead->_prev = cur;
}
}
/*void Erase(ListNode* pos)
{
assert(pos);
if (_phead->_next == _phead)
{
delete pos;
_phead = NULL;
}
else
{
ListNode* prev = pos->_prev;
ListNode* next = pos->_next;
prev->_next = next;
next->_prev = prev;
next->_next = prev;
prev->_prev = next;
_phead = next;
delete pos;
}
}*/
void Erase(ListNode* pos)
{
assert(pos);
if (_phead->_next == _phead)//只有一个节点
{
delete pos;
_phead = NULL;
}
ListNode* next = pos->_next;
ListNode* pre = pos->_prev;
if (pos == _phead)// 删除的节点为头节点
{
next->_prev = pre;
pre->_next = next;
_phead = next;
delete pos;
}
else if (pos->_next == _phead)//删除的节点为尾节点
{
pre->_next = next;
next->_prev = pre;
delete pos;
}
else//删除的节点为中间节点
{
pre->_next = next;
next->_prev = pre;
delete pos;
}
}
public:
DCListNode(ListNode* phead = NULL)
:_phead(phead)
{}
~DCListNode()
{
clear();
}
void clear()
{
if (_phead == NULL)
{
;
}
else if (_phead->_next == _phead)
{
delete _phead;
_phead = NULL;
}
else
{
ListNode* cur = _phead;
while (cur->_next != _phead)
{
ListNode* del = cur;
cur = cur->_next;
delete del;
del = NULL;
}
delete cur;//因为此时cur指向最后一个节点
cur = NULL;
}
}
private:
ListNode* _phead;
};
//test PushBack() PopBack()
void test1()
{
DCListNode s1;
s1.PushBack(1);
s1.PushBack(2);
s1.PushBack(3);
s1.PushBack(4);
s1.PushBack(5);
s1.Print();
s1.PopBack();
s1.Print();
s1.PopBack();
s1.Print();
s1.PopBack();
s1.Print();
s1.PopBack();
s1.Print();
s1.PopBack();
s1.Print();
s1.PopBack();
s1.Print();
}
//test Find() Insert() Erase()
void test2()
{
DCListNode s1;
s1.PushBack(1);
s1.PushBack(2);
s1.PushBack(3);
s1.PushBack(4);
s1.PushBack(5);
cout << (s1.Find(2))->_data << endl;
ListNode* p1 = s1.Find(2);
s1.Insert(p1, 10);
s1.Print();
cout << (s1.Find(5))->_data << endl;
ListNode* p2 = s1.Find(5);
s1.Insert(p2, 20);
s1.Print();
ListNode* p3 = s1.Find(3);
s1.Erase(p3);
s1.Print();
}
int main()
{
//test1();
test2();
system("pause");
return 0;
}