循环链表（测试代码，Qt5.1 for windows）

摘要: 只要将单链表的尾节点和头节点连接起来，单向链表就称为循环链表。

循环链表的原理很简单，这里就不在赘述。下面是循环链表的测试代码：

主函数所在文件：

circularlistwithheader.cpp

/*
* 主函数
*/
#include<iostream>
#include "circularlistwithheader.h"

using namespace std;

int main(int argc, char *argv[])
{
//测试构造函数
circularListWithHeader<int>y,z;
cout<<"Initial size of y and z = "
<<y.size()<<", "
<<z.size() <<endl;

//测试insert()函数
y.insert(0,2);
y.insert(1,6);
cout<<"after insert 2 and 6:";y.output(cout);cout<<endl;

y.insert(0,1);
y.insert(2,4);
cout<<"after insert 1 and 4:";y.output(cout);cout<<endl;

y.insert(3,5);
y.insert(2,3);
cout<<"after insert 5 and 3:";y.output(cout);cout<<endl;

//测试size()函数
cout<<"size of y = "<<y.size()<<endl;

//测试indexOf()函数
int index = y.indexOf(5);
if(index < 0)
{
cout << "4 not fouond" <<endl;
}
{
cout << "The index of 4 is" <<index <<endl;
}

index = y.indexOf(7);
if(index < 0)
{
cout << "7 not found" <<endl;
}
else
{
cout << "The index of 7 is " <<index <<endl;
}
return 0;
}

chainNode.h

/*
*  chainNode.h
*  链表节点定义
*
*/

#ifndef CHAINNODE_H
#define CHAINNODE_H

template<class T>
struct chainNode
{
//数据成员
T element;
chainNode<T> *next;

//方法
chainNode(){}
chainNode(const T& element)
{
this->element = element;
}
chainNode(const T& element,chainNode<T>* next)
{
this->element = element;
this->next = next;
}
};
#endif // CHAINNODE_H

circularListWithHeader.h

/*
* circularListWithHeader.h
* 循环链表实体类定义
*/

#ifndef CIRCULARLISTWITHHEADER_H
#define CIRCULARLISTWITHHEADER_H

#include<iostream>
#include<sstream>
#include<string>
#include "chainnode.h"
#include "myexceptions.h"

using namespace std;

template<class T>
class circularListWithHeader
{
public:
//构造函数
circularListWithHeader();

/*
* 一些其他函数
*/
//返回链表中元素个数
int size() const {return listSize;}
int indexOf(const T& theElement) const;
void insert(int theIndex,const T& theElement);
void output(ostream& out) const;
protected:
//检查索引是否合法
void checkIndex(int theIndex) const;

chainNode<T>* headerNode;//指向头节点
int listSize;//元素个数
};

/*
* 类中各个函数的具体实现
*
*/
template<class T>
circularListWithHeader<T>::circularListWithHeader()
{
headerNode = new chainNode<T>();
headerNode->next = headerNode;
listSize = 0;
}

template<class T>
void circularListWithHeader<T>::checkIndex(int theIndex) const
{
if(theIndex < 0 || theIndex >= listSize)
{
ostringstream s;
s <<"index = "<<theIndex<<" size = "<<listSize;
throw illegalIndex(s.str());
}
}

template<class T>
int circularListWithHeader<T>::indexOf(const T &theElement) const
{
headerNode->element = theElement;

chainNode<T>* currentNode = headerNode->next;
int index = 0;
while(currentNode->element != theElement)
{
currentNode = currentNode->next;
index++;
}
if(currentNode == headerNode)
return -1;
else
return index;
}

template<class T>
void circularListWithHeader<T>::insert(int theIndex, const T &theElement)
{
if(theIndex < 0 || theIndex > listSize)
{
ostringstream s;
s<<"index = "<<theIndex<<" size = "<<listSize;
throw illegalIndex(s.str());
}

chainNode<T>* p = headerNode;
for(int i = 0;i< theIndex;i++)
{
p = p->next;
}
p->next = new chainNode<T>(theElement,p->next);
listSize++;
}

template<class T>
void circularListWithHeader<T>::output(ostream &out) const
{
for(chainNode<T>* currentNode = headerNode->next;
currentNode != headerNode;
currentNode = currentNode->next)
out<<currentNode->element<<" ";
}

//<<的重载
template<class T>
ostream& operator <<(ostream& out,const circularListWithHeader<T>& x)
{
x.output(out);
return out;
}

#endif // CIRCULARLISTWITHHEADER_H

myExceptions.h

/*
* myExceptions.h
* 这个类包含类对各种异常的处理类
*/
#ifndef MYEXCEPTIONS_H
#define MYEXCEPTIONS_H

#include<string>
using namespace std;

//不合法的参数值
class illegalParameterValue
{
public:
illegalParameterValue(string theMessage = "Illegal patameter value")
{
message = theMessage;
}
void outputMessage()
{
cout<<message<<endl;
}
private:
string message;
};

//输入数据不合法
class illegalInputData
{
public:
illegalInputData(string theMessage = "Illegal data input")
{
message = theMessage;
}
void outputMessage()
{
cout <<message <<endl;
}
private:
string message;
};

//索引不合法
class illegalIndex
{
public:
illegalIndex(string theMessage = "Illegal index")
{
message = theMessage;
}
void outputMessage()
{
cout<<message<<endl;
}
private:
string message;
};

#endif // MYEXCEPTIONS_H