线性表——（2）单向链表

// "ListNode.h"

#include <iostream>
using namespace std;

template<class T>
class ListNode
{
public:
	ListNode():p_next(NULL){ }
	ListNode(const T item, ListNode<T>* next = NULL):data(item), p_next(next){ }
	T GetData();
protected:
	T data;	// 存放节点值
	ListNode* p_next;	// 存放后继地址
};

template<class T>
T ListNode<T>::GetData()
{
	return this->data;
}

// SingleList.h

#include "ListNode.h"

template<class T>
class SingleList
{
public:
	SingleList();
	~SingleList();
	int Length();	// 链表长度
	void Clear();	// 清空链表
	int Find(int n, T &targ);	// 查找n号节点，值存入targ
	int Insert(int n, T targ);	// 将targ插入n号位置
	int Delete(int n);	// 删除第n个元素


private:
	ListNode<T>* head;	// 存储一个T的节点指针head
};

template<class T>
inline SingleList<T>::SingleList()
{
	head = new ListNode<T>();
}

template<class T>
inline SingleList<T>::~SingleList()
{
	Clear();
	delete head();
}

template<class T>
int SingleList<T>::Length()
{
	ListNode<T>* p = head->p_next;
	int count = 0;
	while (p != NULL) {
		++count;
		p = p->p_next;
	}
	return count;
}

template<class T>
void SingleList<T>::Clear()
{
	ListNode<T>* pdel;	// 从前到后依次删除连接,直到指向NULL的指针也被删除
	while (head->p_next != NULL) {

		pdel = head->p_next;
		head->p_next = pdel->p_next;
		delete pdel;
	}
}

template<class T>
int SingleList<T>::Find(int n, T & targ)
{
	if (n < 0 || n > Length()) {
		cout << "Illegal opration!" << endl;
		return 0;
	}
	ListNode<T>* p = head->p_next;
	for (int i = 0; i <= n; && p ++i) {
		p = p->p_next;

	}
	if (p == NULL) {
		cout << "overflow" << endl;
		return 0;
	}
	targ = p->data;
	return 1;
}

template<class T>
int SingleList<T>::Insert(int n, T targ)
{
	if (n < 0 || n > Length()) {
		cout << "Illegal n" << endl;
		return 0;
	}
	ListNode<T>* p = head;
	ListNode<T>* p_new = new ListNode<T>(targ, NULL);
	if (p_new == NULL) {
		cout << "Node Error" << endl;
		return 0;
	}
	for (int i = 0; i < n; ++i) {
		p = p->p_next;
	}
	p_new->p_next = p->p_next;
	p_next = p_new;
	return 1;
}

template<class T>
int SingleList<T>::Delete(int n)
{
	if (n < 0 || n > Length()) {
		cout << "Illegal n" << endl;
		return 0;
	}
	ListNode<T>* p = head;
	ListNode<T>* pdel;
	for (int i = 0; i < n && p->p_next; ++i) {
		p = p->p_next;
	}
	pdel = p;
	p->p_next = pdel->p_next;
	T data = pdel->data;
	delete pdel;
	return 1;
}