C++实现单链表的几个基本功能

闲来无事，自己动手实现了单链表的一些基本操作（增、删、改、查）以及一些附属的功能。

链表的头文件如下：

#ifndef CLINK_H_
#define CLINK_H_

typedef int elemType;//元素项

struct Item //节点项
{
elemType data;
Item *p_next;
};

class CLink
{
public:
CLink();//构造函数
CLink(const CLink & link); //拷贝构造函数
CLink & operator = (const CLink & otherLink); //赋值函数

void rearAdd(elemType data); //在末尾添加元素;
void headAdd(elemType data); //在头部添加元素;
void print() const; //遍历链表并打印;
void destroy();//销毁链表，将链表成为空链表;
int size() const; //得到单链表的长度;
bool isEmpty();// 判断链表是否为空;
elemType getElement(int pos) const; //获得链表中第pos个节点的元素;
int find(elemType x); //查找x第一次出现的位置，若没有，返回-1;
void modifyElement(int pos, elemType x); //修改pos位置的元素值为x;
void insertElement(int pos, elemType data);//将元素插入在链表的第pos位置上;
void deleteElement(int pos); //删除链表的第pos个节点;

void sort(); //对链表元素进行升序排序;

~CLink();
private:
Item *pHead; //头节点
int length; //链表长度
};

#endif

基本功能实现如下：

1.末尾追加元素

void CLink::rearAdd(elemType data)
{

if(!pHead) //若添加时为空链表
{
pHead = new Item;
pHead->data = data;
pHead->p_next = NULL;
}
else
{
Item *temp = pHead;
while(temp->p_next)
{
temp = temp->p_next;
}
temp->p_next = new Item;
temp = temp->p_next;

temp->data = data;
temp->p_next = NULL;
}
length++;
}

2.首部添加元素

void CLink::headAdd(elemType data)
{
Item * addElement = new Item;
addElement->data = data;
addElement->p_next = NULL;

if(!pHead)//添加时为空链表
{
pHead = addElement;
}
else
{
addElement->p_next = pHead;
pHead = addElement;
}
}

3.遍历链表并打印元素

void CLink::print() const
{
Item *temp = pHead;
int count = 0;
while(temp)
{
cout << temp->data << "\t";
count++;

if(count % 5 == 0)
{
cout << endl;
}

temp = temp->p_next;
}
}

4.获得链表长度

int CLink::size() const
{
return length;
}

5.判断链表是否为空

bool CLink::isEmpty()
{
return pHead == NULL;
}

6.获得第pos个节点的元素

elemType CLink::getElement(int pos) const
{
if(pos < 1 || pos > length)
{
throw "获得元素位置非法！";
}
int index = 0;
Item *temp = pHead;
while(temp && ++index < pos)
{
temp = temp->p_next;
}

return temp->data;
}

7.查找x第一次出现的位置，若没有，返回-1

int CLink::find(elemType x)
{
Item *temp = pHead;
int index = 0;

while(temp && ++index <= length)
{
if(temp->data == x)
{
return index;
}
temp = temp->p_next;
}

return -1;
}

8.修改第pos个节点的值

void CLink::modifyElement(int pos, elemType x)
{
if(pos < 1 || pos > length)
{
throw "修改节点位置pos非法！";
}

Item *temp = pHead;
int index = 0;
while(temp && ++index <= length)
{
if(index == pos)
{
temp->data = x;
return ;
}
temp = temp->p_next;
}
}

9.将元素插入在链表的第pos位置上

void CLink::insertElement(int pos, elemType data)
{
if(pos < 1 || pos > length + 1)
{
throw "插入pos位置不合法！";
}

Item * insertElement = new Item;
insertElement->data = data;
insertElement->p_next = NULL;

if(pos == 1)//pos在链表的头位
{
insertElement->p_next = pHead;
pHead = insertElement;
length++;
}
else
{
Item *temp = pHead;
int index = 0;
while(temp && ++index <= length)
{
if(index + 1 == pos)
{
insertElement->p_next = temp->p_next;
temp->p_next = insertElement;

length++;

return ;
}
temp = temp->p_next;
}
}
}

10.删除链表的第pos个节点

void CLink::deleteElement(int pos)
{
if(pos < 1 || pos > length)
{
throw "删除位置pos非法！";
}

Item * deleteElement;
if(pos == 1)
{
deleteElement = pHead;
pHead = pHead->p_next;
delete deleteElement;
length--;
}
else
{
Item *temp = pHead;
int index = 0;
while(temp && ++index < length)
{
if(index + 1 == pos)
{
deleteElement = temp->p_next;
temp->p_next = temp->p_next->p_next;
delete deleteElement;

length--;
return ;
}
temp = temp->p_next;
}
}
}

11.对节点进行升序排序

void CLink::sort()
{
bool sortflags;
elemType a, b;
for(int i = 1; i < length ; i++)
{
sortflags = true;
for(int j = 1; j <= length - i; j++)
{
if( ( a = getElement(j) ) > (b = getElement(j+1) ) )
{
modifyElement(j, b);
modifyElement(j+1, a);

sortflags = false;
}
}
if(sortflags)
return ;
}
}

12.销毁链表并置为空链表

void CLink::destroy()
{
Item *temp;
while(pHead)
{
temp = pHead;
pHead = pHead->p_next;
delete temp;
}
length = 0;
}

对有指针成员的类处理（利用上面实现的功能进行处理）：

1.构造函数

CLink::CLink():pHead(NULL),length(0){};

2.拷贝构造函数

CLink::CLink(const CLink & otherLink):pHead(NULL),length(0)
{

for(int i = 1; i <= otherLink.length; i++)
{
rearAdd(otherLink.getElement(i));
}
}

3. =运算符重载

CLink & CLink::operator =(const CLink & otherLink)
{
destroy();
for(int i = 1; i <= otherLink.length; i++)
{
rearAdd(otherLink.getElement(i));
}
return *this;
}

4. 析构函数

CLink::~CLink()
{
Item *temp;
while(pHead)
{
temp = pHead;
pHead = pHead->p_next;
delete temp;
}
}