针对上次写的单链表中不足的地方进行修改：

1.构造函数需要让用户输入（bad）

2.函数功能不单一，既操作链表，还打印输出（bad）

代码链接（包含无头\有头单链表、循环单链表、双链表、循环双链表）

接口 singleList.h

//
// Created by mingm on 2019/3/18.
//
#ifndef _SINGLELIST_H
#define _SINGLELIST_Hstruct SNode		//结点的基本数据类型
{int data;SNode* pNext;
};typedef unsigned int UINT;
typedef SNode* ListNode;class SingleList
{public:SingleList(void);~SingleList(void);bool IsEmpty() const;//判断链表是否为空UINT GetLength() const;//获取当前链表的长度ListNode GetHeadNode() const;//获取链表的头结点ListNode GetTailNode() const;//获取链表的尾结点ListNode GetMidNode();//获得链表的中间结点void AddHead(const int &data);//在链表的头部插入新的结点void AddTail(const int &data);//在链表的尾部插入新的结点bool posInList(ListNode pos);//检查节点指针是否在链表中ListNode InsertAt(ListNode pos, const int &data);//在指定结点前插入数据，并返回新结点的地址ListNode ModifyAt(ListNode pos, const int &data);//修改指定结点的数据，并返回当前节点的地址ListNode RemoveAt(ListNode pos);//删除指定结点，并返回被删除结点的下一结点的地址ListNode RemoveAtBack(UINT nCountBack);//删除倒数第n个节点，并返回被删除结点的下一结点的地址ListNode Find(const int &data);//在当前链表中找到和要查找数据相等的第一个结点的地址void Erase();//删除链表的所有结点void PrintList() const;//打印链表所有结点的数据void Reverse();//反转链表private:ListNode m_pHead;   //头结点UINT m_nListLen;    //链表数据长度
};#endif

类实现文件 singleList.cpp

//单向链表（不带头）
// Created by mingm on 2019/3/18.
//
#include "singleList.h"
#include <iostream>SingleList::SingleList():m_pHead(NULL),m_nListLen(0){}SingleList::~SingleList()
{Erase();
}
void SingleList::Erase()
{if(m_pHead != NULL){ListNode temp = m_pHead, del;while(temp != NULL){del = temp;temp = temp->pNext;delete del;}m_pHead = NULL;m_nListLen = 0;}
}
bool SingleList::IsEmpty() const
{return m_pHead == NULL;
}
UINT SingleList::GetLength() const
{return m_nListLen;
}
ListNode SingleList::GetHeadNode() const
{return m_pHead;
}
ListNode SingleList::GetTailNode() const
{if(!m_pHead)return NULL;ListNode temp = m_pHead;while(temp->pNext != NULL){temp = temp->pNext;}return temp;
}
ListNode SingleList::GetMidNode()   //快慢指针法
{ListNode fast = m_pHead, slow = m_pHead;while(fast){if(fast->pNext != NULL){fast = fast->pNext->pNext;}else{break;}slow = slow->pNext;}//简洁写法
//    while(fast && fast->pNext)
//     {
//        fast = fast->pNext->pNext;
//        slow = slow->pNext;
//     }return slow;
}
void SingleList::AddHead(const int &data)
{ListNode newNode = new SNode;newNode->data = data;newNode->pNext = NULL;if(m_pHead == NULL){m_pHead = newNode;}else{newNode->pNext = m_pHead;m_pHead = newNode;}m_nListLen++;
}
void SingleList::AddTail(const int &data)
{ListNode newNode = new SNode;newNode->data = data;newNode->pNext = NULL;if(m_pHead == NULL){m_pHead = newNode;}else{GetTailNode()->pNext = newNode;}m_nListLen++;
}
bool SingleList::posInList(ListNode pos)
{if(m_pHead == NULL)return false;else{ListNode temp = m_pHead;while(temp && temp != pos){temp = temp->pNext;}if(temp == NULL)    //指针地址不在链表内return false;elsereturn true;}
}
ListNode SingleList::InsertAt(ListNode pos, const int &data)
{if(pos == NULL)return NULL;else if(pos == m_pHead){AddHead(data);return m_pHead;}else{ListNode temp = m_pHead;ListNode preNode = NULL;while(temp && temp != pos){preNode = temp;temp = temp->pNext;}if(temp == NULL)    //指针地址不在链表内return NULL;else{ListNode newNode = new SNode;newNode->data = data;newNode->pNext = NULL;newNode->pNext = pos;preNode->pNext = newNode;m_nListLen++;return newNode;}}
}
ListNode SingleList::ModifyAt(ListNode pos, const int &data)
{if(!posInList(pos))return NULL;else{pos->data = data;return pos;}
}
ListNode SingleList::RemoveAt(ListNode pos)
{if(!posInList(pos))return NULL;else{ListNode temp = m_pHead;if(pos == m_pHead){temp = pos->pNext;delete pos;m_nListLen--;m_pHead = temp;return temp;}else{while(temp->pNext != pos){temp = temp->pNext;}temp->pNext = pos->pNext;delete pos;m_nListLen--;return temp->pNext;}}
}
ListNode SingleList::RemoveAtBack(UINT nCountBack)//先让快指针先走n-1步，然后快慢指针一起动，快指针到达尾部，慢指针指向倒数第n个
{if(nCountBack == 0 || nCountBack > m_nListLen)return NULL;else{ListNode fast = m_pHead;ListNode slow = m_pHead;for(int i = 0; i < nCountBack-1 && fast; ++i){fast = fast->pNext;}while(fast->pNext){fast = fast->pNext;slow = slow->pNext;}fast = RemoveAt(slow);return fast;}
}
ListNode SingleList::Find(const int &data)
{ListNode temp = m_pHead;while(temp && temp->data != data){temp = temp->pNext;}return temp;
}
void SingleList::PrintList() const
{std::cout << "----- print start ----" << std::endl;ListNode temp = m_pHead;for(int i = 0; i < m_nListLen && temp; ++i){std::cout << "No. " << i+1 << " node is " << temp->data << std::endl;temp = temp->pNext;}std::cout << "----- print end ----" << std::endl;
}
void SingleList::Reverse()  //就地反转法
{if(m_pHead && m_pHead->pNext){ListNode preNode, curNode, tempNode;preNode = curNode = tempNode = m_pHead;curNode = preNode->pNext;preNode->pNext = NULL;while(curNode->pNext){tempNode = curNode;curNode = curNode->pNext;tempNode->pNext = preNode;preNode = tempNode;}curNode->pNext = preNode;m_pHead = curNode;}
}

测试主程序 test_singleList.cpp

测试程序包含长度从0开始的 list，以便检查边界情况下程序是否正常运行。

//
// Created by mingm on 2019/3/20.
//
#include "singleList.cpp"
#include <iostream>
using namespace std;
int main()
{for(int k = 0; k < 5; ++k){cout << "------------ test start ----------------" << endl;SingleList intList;if(intList.IsEmpty())cout << "empty list!" << endl;cout << intList.GetLength() << " node(s) !" << endl;cout << "---------------" << endl;cout << "add 0  to " << k-1 << " into list: " << endl;for(int j = 0; j < k; ++j){intList.AddTail(j);}cout << intList.GetLength() << " node(s) !" << endl;intList.PrintList();cout << "------------- reverse list" << endl;intList.Reverse();intList.PrintList();if(intList.GetHeadNode()){cout << "head node: " << intList.GetHeadNode()->data << endl;cout << "tail node: " << intList.GetTailNode()->data << endl;cout << "middle node: " << intList.GetMidNode()->data << endl;}cout << "--------------- addTail " << k << endl;intList.AddTail(k);intList.PrintList();if(intList.posInList(intList.GetMidNode()))cout << "midNode in List !" << endl;cout << "100 insert at midNode ";if(intList.GetMidNode())cout << intList.GetMidNode()->data ;cout << " front " << endl;intList.InsertAt(intList.GetMidNode(),100);intList.PrintList();cout << "modify head to 99 " << endl;intList.ModifyAt(intList.GetHeadNode(),99);intList.PrintList();cout << "del Tail" << endl;intList.RemoveAt(intList.GetTailNode());intList.PrintList();cout << "del the " << intList.GetLength()-1 << "th node count from end !" << endl;intList.RemoveAtBack(intList.GetLength()-1);intList.PrintList();cout << "address of first " << k-3 << " is ";if(intList.Find(k-3))cout << intList.Find(k-3) << endl;elsecout << "not exits !" << endl;}return 0;
}

Valgrind检查内存是否泄漏（部分结果展示如下）