数据结构（C++）——单向循环链表

#include"AllHead.h"

template<class T>
class CircList;

template<class T>
class CircListNode
{
friend class CircList<T>;
protected:
T data;
CircListNode *next;
public:
CircListNode(CircListNode<T> *ptr = NULL){next = ptr;}              //只初始化指针域的构造函数
CircListNode(T x,CircListNode<T> *ptr = NULL){data = x;next = ptr;}//初始化数据域和指针域的构造函数
};

template<class T>
class CircList
{
private:
CircListNode<T> *first;
CircListNode<T> *last;
size_t size;
public:
CircList()
{
first = new CircListNode<T>;
last = first;
last->next = first;
size = 0;
}
~CircList(){makeEmpty();}
void makeEmpty();
Status IsEmpty(){return first == last?TRUE:FALSE;}
Status push_back(T x);
void show_circlist();
Status push_front(T x);
size_t getlenth(){return size;}
T getHead_val(){return first!=last?first->next->data:NULL;}
T getLast_val(){return first!=last?last->data:NULL;}
Status pop_back();
Status pop_front();
CircListNode<T>* find(T key);
Status insert_val(T x);
Status del_val(T x);
void sort();
void reverse();
//  List(ListNode<T> &L);
//	ListNode<T>* getFirst(){return first;}
//	List& operator=(List<T> &L);
};
template<class T>
void CircList<T>::sort()///////////////////////////SORT//////////////
{
CircListNode<T> *q = first->next;
CircListNode<T> *h;
CircListNode<T> *p;
CircListNode<T> *m;
first->next = first;
last = first;
while(q!= first)
{//h和q是断开后面的指针！！！
h = q;
q = q->next;
//p和m是新的表头这边的两个指针！！！
p = first->next;
m = first;
while(p != first&&(p->data)<(h->data))
{
m = p;
p = p->next;
}
if(p == first)
{
last = h;
}
m->next = h;
h->next = p;
}
}
template<class T>
void CircList<T>::reverse()
{
if(IsEmpty())
{
cout<<"空链表无法逆置"<<endl;
}
CircListNode<T> *h = first->next->next;
CircListNode<T> *q = h->next;
CircListNode<T> *m = last;
last = first->next;
last->next = first;

while(q!=first)
{
h->next = first->next;
first->next = h;
h = q;
q = q->next;
}
m->next = first->next;
first->next = m;
}
template<class T>
Status CircList<T>::del_val(T x)
{
if(IsEmpty())
{
cout<<"链表已空(del_val)....."<<endl;
return ERROR;
}
CircListNode<T> *q = first->next;
CircListNode<T> *h = first;
size_t sizemem = size;
while(q!= first)
{
if(q->data == x)
{
if(q->next == first)
{
last = h;
}
h->next = q->next;
delete q;
--size;
return OK;
}
h = q;
q = q->next;
}
if(size == sizemem)
{
cout<<"链表中不存在该值！"<<endl;
return ERROR;
}
}

template<class T>
Status CircList<T>::insert_val(T x)
{
CircListNode<T> *p = new CircListNode<T>;
p->data = x;
p->next = NULL;
CircListNode<T> *q = first->next;
CircListNode<T> *h = first;
while(q!= first && q->data<x)
{
h = q;
q = q->next;
}
if(q == first)
{
last = p;
}
p->next = q;
h->next = p;
++size;
return OK;
}
template<class T>
CircListNode<T>* CircList<T>::find(T key)
{
if(IsEmpty())
{
cout<<"链表为空()find..."<<endl;
}
CircListNode<T> *q = first->next;
while(q != first&&q->data != key)
{
q=q->next;
}
if(q == first)
{
return NULL;
}
else
{
return q;
}

}
template<class T>
Status CircList<T>::pop_front()
{
if(IsEmpty())
{
cout<<"空链表不能删除(pop_front)......"<<endl;
return ERROR;
}
CircListNode<T> *q = first->next;
first->next = q->next;
delete q;
if(size == 1)
{
last = first;
}
--size;
return OK;
}
template<class T>
Status CircList<T>::pop_back()
{
if(IsEmpty())
{
cout<<"空链表不能删除(pop_back)......"<<endl;
return ERROR;
}
CircListNode<T> *q = first;
while(q->next!=last)
{
q=q->next;
}
q->next = first;
delete last;
last = q;
--size;
return OK;
}
template<class T>
Status CircList<T>::push_front(T x)
{
CircListNode<T> *s = new CircListNode<T>;
s->data = x;
s->next = first->next;
first->next = s;
if(size == 0)
{
last = s;
}
++size;
return OK;
}
template<class T>
void CircList<T>::show_circlist()
{
CircListNode<T> *p = first;
while(p->next != first)
{
p=p->next;
cout<<p->data<<"-->";
}
cout<<"NULL"<<endl;
}
template<class T>
Status CircList<T>::push_back(T x)
{
CircListNode<T> *s = new CircListNode<T>;
s->data = x;
last->next = s;
last = s;
last->next = first;
++size;
return OK;
}

template<class T>
void CircList<T>::makeEmpty()
{
if(IsEmpty())
{
cout<<"链表已空..."<<endl;
}
else
{
CircListNode<T> *q;
while(first->next != first)
{
q = first->next;
first->next = q->next;
delete q;
}
last = first;
size = 0;
}
}

#if 1#include"CircList.h"int main(){    CircList<int> myls;CircList<int> yourls;int select = 1;while(select){cout<<"||========================================||"<<endl;cout<<"||==[1]push_front    [2]push_back=======||"<<endl;cout<<"||==[3]show_list     [4]getlenth========||"<<endl;cout<<"||==[5]getHead_val    [6]getLast_val=====||"<<endl;cout<<"||==[7]quit                          ||"<<endl;cout<<"||==[9]makeEmpty     [10]pop_back=======||"<<endl;cout<<"||==[11]pop_front    [12]insert_val=====||"<<endl;cout<<"||==[13]del_val      [14]sort==========||"<<endl;cout<<"||==[15]reverse      [16]find_val_rid==||"<<endl;  cout<<"||========================================||"<<endl;cout<<"请输入您的选择：>";cin>>select;system("cls");switch(select){case 1:int val_pf;cout<<"请输入插入的值(以-1结束)：>"<<endl;while(cin>>val_pf,val_pf!=-1){myls.push_front(val_pf);}break;case 2:int val_pb;cout<<"请输入插入的值(以-1结束)：>"<<endl;while(cin>>val_pb,val_pb!=-1){myls.push_back(val_pb);}break;case 3:     		myls.show_circlist();break;case 4:size_t size;size = myls.getlenth();cout<<"循环链表长度为："<<size<<endl;break;case 5:int head;head = myls.getHead_val();cout<<"该链表的第一个为："<<head<<endl;break;case 6:int last;last = myls.getLast_val();cout<<"该链表的最后一个值为："<<last<<endl;break;case 7:exit(1);break;case 9:myls.makeEmpty();break;case 10:myls.pop_back();break;case 11:myls.pop_front();break;case 12:int val_insert;cout<<"请输入您要插入的值：>";cin>>val_insert;myls.insert_val(val_insert);break;case 13:int val_del;cout<<"请输入您要删除的值：>";cin>>val_del;myls.del_val(val_del);break;case 14:myls.sort();break;case 15:myls.reverse();break;case 16:CircListNode<int> *key;int key_find;cout<<"请输入您要查找的值；>";cin>>key_find;key = myls.find(key_find);if(key != NULL)cout<<"找到啦！-->"<<key<<endl;elsecout<<"没找到..."<<endl;break;}}return 0;}#endif