C++实现数据结构四 单循环链表

template<typename Type> class CircularList; //不能写成：CircularList<Type>

//重载操作数声明，注意和在类中友元证明方式的区别
//template<typename Type> class ListNode;
//template<typename Type>
//ostream& operator<< (ostream &os, ListNode<Type>  &node);

template<typename Type> class ListNode
{
private:
friend class CircularList<Type>;
friend ostream& operator<< <Type>(ostream&, ListNode<Type>&);
ListNode(): next(NULL) {}
ListNode(const Type item, ListNode<Type> *p=NULL ): data(item), next(p) {}
~ListNode()
{
next = NULL;
}

private:
Type data;
ListNode *next;
};
template<typename Type>
ostream& operator<< (ostream &os, ListNode<Type>  &node)
{
os<<node.data;
return os;
}

#include "ListNode.h"

template<typename Type> class CircularList
{
public:
CircularList()
{
head = new ListNode<Type>();
head->next = head;
}
~CircularList()
{
MakeEmpty();
delete head;
}

public:
void MakeEmpty();
int Length();
ListNode<Type> *Find(int n);
bool Insert(Type item, int n=0);
Type Remove(int n=0);
bool RemoveAll(Type item);
Type Get(int n);
void Print();

private:
ListNode<Type> *head;
};

template<typename Type>
void CircularList<Type>::MakeEmpty()
{
ListNode<Type> *pmove = head->next ;
ListNode<Type> *pdel;
while(pmove != head)
{
pdel=pmove;
pmove = pmove->next;
delete pdel;
pdel = NULL;
}
}

template<typename Type>
int CircularList<Type>::Length()
{
ListNode<Type> *pmove = head;
int count = 0;
while(pmove->next != head)
{
++count;
pmove = pmove->next;
}
return count;
}

template<typename Type>
ListNode<Type>* CircularList<Type>::Find(int n)
{
if(n<1)
{
cout<<"the n is illegal"<<endl;
return NULL;
}

ListNode<Type> *pmove = head;
for(int i=0; i<n; ++i)
{
pmove = pmove->next;
if(pmove == head)
{
cout<<"the n is out of the boundary"<<endl;
return NULL;
}
}

return pmove;
}

template<typename Type>
bool CircularList<Type>::Insert(Type item, int n=0)
{
if(n<0)
{
cout<<"The n is illegal"<<endl;
}

ListNode<Type> *pmove = head;
for(int i=0; i<n; ++i)
{
pmove = pmove->next;
if(pmove == head)
{
cout<<"the n is out of the boundary, so cannot insert the data"<<endl;
return false;
}
}
ListNode<Type> *pnode = new ListNode<Type>();
pnode->data = item;
pnode->next = pmove->next;
pmove->next = pnode;
return true;

}

template<typename Type>
Type CircularList<Type>::Remove(int n=0)
{
if(n < 1)
{
cout<<"the n is illegal"<<endl;
return 0;
}
ListNode<Type> *pmove = head, *pdel;
for(int i = 0; i< (n-1) && pmove->next != head ; ++i)
{
pmove= pmove->next;

}
if(pmove->next == head)
{
cout<<"the n is out of boundary"<<endl;
return 0;
}

pdel = pmove->next;
pmove->next = pdel->next;
Type item = pdel->data;
delete pdel;
return item;

}

template<typename Type>
bool CircularList<Type>::RemoveAll(Type item)
{
ListNode<Type> *pmove= head->next, *pdel, *p= head;
int count =0;
while(pmove != head)
{
//p->next = pmove;
//p = p->next;
if(pmove->data == item)
{
++count;
pdel =pmove;
pmove = pmove->next;
p->next =pmove;
delete pdel;
pdel = NULL;
}
else
{
pmove = pmove->next;
p= p->next ;
}

}
if(count == 0)
return false;
else
return true;
}

template<typename Type>
Type CircularList<Type>::Get(int n)
{
ListNode<Type> *p = Find(n);
if(p == NULL)
{
cout<<"cannot get the data at "<<n<<endl;
return 0;
}
return p->data;
}

template<typename Type>
void CircularList<Type>::Print()
{
ListNode<Type> *pmove = head->next;

cout<<"head-->";
while(pmove != head)
{
cout<<pmove->data<<"-->";
pmove = pmove->next;
}
cout<<"voer"<<endl;
}