【复习】C++之MyList

 设计原则：单一职责

可读性，维护修改，安全，构造析构

#include<iostream>
using namespace std;
 
struct Node
{
	int nValue;
	Node* pNext;
};

class CList   //链表类
{
private:
	Node* m_pHead;  //链表头尾，长度
	Node* m_pEnd;
	int m_nLength;
public:
	Node* begin()   //接口函数
	{
		return m_pHead;
	}
	Node* end()
	{
		return NULL;
	}
public:
	CList()   //创建空链表
	{
		m_pHead = NULL;
		m_pEnd = NULL;
		m_nLength = 0;
	}
	CList(int nCount)  //创建有nCount个结点的链表
	{
		// 初始化成员变量
		m_pHead = NULL;
		m_pEnd = NULL;
		m_nLength = 0;
 
		for (int i = 0;i < nCount;i++)
		{
			Push_Back(0);
		}
	}
	~CList()
	{
		while(m_pHead)
			Pop_Front();
	}
public:
	void Push_Back(int nValue)  //在链表上添加一个数
	{
	    //创建一个结点，把值装进去
		Node* node = new Node;
		node->nValue = nValue;
		node->pNext = NULL;
 
		//把这个结点放到链表的尾部
		if(!m_pHead)  //如果现在没有链表的时候
		{
			m_pHead = node;
			m_pEnd = node;
		}
		else   //链表有结点的时候
		{
			m_pEnd->pNext = node;
			m_pEnd = node;
		}
		m_nLength++;
	}
	void Pop_Front()  //删除一个链表结点
	{
		//判断链表有没有结点
		if(m_pHead == NULL)
			return;
		//只有一个结点的时候
		if(m_pHead == m_pEnd)
		{
			delete m_pHead;
			m_pHead = NULL;
			m_pEnd = NULL;
			m_nLength = 0;
			return ;
		}
		//有多个结点的时候
		Node *pDel = m_pHead;
		m_pHead = m_pHead->pNext;
		delete pDel;
		pDel = NULL;
		m_nLength--;
	}
	void Show()  //测试代码
	{
		Node* pTemp = m_pHead;
		while (pTemp)
		{
			cout << pTemp->nValue <<" ";
			pTemp = pTemp->pNext;
		}
		cout << "nLength:"<<m_nLength<<endl;
	}
};
 
int main()
{
    //------------------------------------------
	CList lst1;
	lst1.Show();
	CList lst2(10);
	lst2.Show();
	lst1.Push_Back(1);
	lst1.Show();
	lst2.Pop_Front();
	lst2.Show();

    //------------通过调用接口使用链表------------
	CList lst;
	lst.Push_Back(1);
	lst.Push_Back(2);
	lst.Push_Back(3);
	lst.Push_Back(4);

	Node* pTemp = lst.begin();
	while(pTemp != lst.end())
	{
		cout << pTemp->nValue << " ";
		pTemp = pTemp->pNext;
	}
 
	system("pause");
	return 0;
}