线性链表的简单实现

近日在复习数据结构，贴一下练习写的代码，线性链表：

// 如果这段代码对你有用，请任意处置。

#include <iostream>
#include <cstdlib>

using namespace std;

template<class Type> class LinkList;

template<class Type> class SNode
{
	friend class LinkList<Type>;
	private:
		Type data;
		SNode<Type> *next;
};

template<class Type> class LinkList
{
	public:
		LinkList();
		~LinkList();

		int Length();
		void Insert(Type a, Type b);// insert element b after a
		bool Delete(Type item);
		SNode<Type> *Find(Type item);
		bool isEmpty();
		void Clear();
		Type GetData(const SNode<Type> *p);
		SNode<Type> *NextOf(const SNode<Type> *p);
	
	private:
		SNode<Type> *head;
};

template<class Type> LinkList<Type>::LinkList()
{
	head = NULL;
}
template<class Type> LinkList<Type>::~LinkList()
{
	Clear();
}
template<class Type> int LinkList<Type>::Length()
{
	int len = 0;
	SNode<Type> *p = head;
	while(p)
	{
		len++;
		p = p->next;
	}
	
	return len;
}
template<class Type> SNode<Type> *LinkList<Type>::Find(Type item)
{
	SNode<Type> *p = head;
	while(p)
	{
		if(p->data == item)
		{
			return p;
		}
		p = p->next;
	}
	return NULL;
}
template<class Type> void LinkList<Type>::Insert(Type a, Type b)
{
	SNode<Type> *p = NULL;
	SNode<Type> *newp = NULL;

	if(head == NULL)
	{
		newp = new SNode<Type>;
		newp->data = b;
		newp->next = NULL;
		head = newp;
	}
	else if((p = Find(a)) != NULL)
	{
		newp = new SNode<Type>;
		newp->data = b;
		p->next = newp;
		newp->next = NULL;
	}
}
template<class Type> bool LinkList<Type>::Delete(Type item)
{
	SNode<Type>* p = head, *q = NULL;
	while(p!=NULL)
	{
		if(p->data == item) break;
		q = p;
		p = p->next;
	}
	if(q==NULL)
	{
		head = p->next;
		delete p;
	}
	else if(p == NULL)
	{
		return false;
	}
	else
	{
		q->next = p->next;
		delete p;
	}
	return true;
}
	
template<class Type> Type LinkList<Type>::GetData(const SNode<Type> *p)
{
	if(p!=NULL)
		return p->data;
	else
	{
		cerr<<"Error: ..."<<endl;
		exit(1);
	}
}
template<class Type> SNode<Type> *LinkList<Type>::NextOf(const SNode<Type> *p)
{
	if(p!=NULL)
		return p->next;
	else
	{
		cerr<<"Error: ..."<<endl;
		exit(1);
	}
}
template<class Type> bool LinkList<Type>::isEmpty()
{
	return head==NULL;
}
template<class Type> void LinkList<Type>::Clear()
{
	SNode<Type> *p = head, *q = NULL;
	while(p)
	{
		q = p;
		p = p->next;
		delete q;
	}
	head = NULL;
}
int main()
{
	LinkList<int> ll;
	SNode<int> *node;

	ll.Insert(0,100);
	ll.Insert(100,200);

	cout<<"Length of ll: "<<ll.Length()<<endl;

	node = ll.Find(100);
	if(node != NULL)
	{
		cout<<ll.GetData(ll.NextOf(node))<<endl;
	}

	ll.Delete(200);
	node = ll.Find(200);
	if(node != NULL)
	{
		cout<<ll.GetData(node)<<endl;
	}
	else
	{
		cout<<"can't find 200"<<endl;
	}

	if(!ll.isEmpty())
	{
		cout<<"not empty"<<endl;
		ll.Clear();
	}
	if(ll.isEmpty()) cout<<"empty now"<<endl;

	return 0;
}