实现了链表的一些常见操作

/*
* 作者：     达闻东
* 修改日期： 2010-04-28 17:10
* 描述：     实现链表的常见操作
*
*/
#include<iostream>
#include<iomanip>
using namespace std;
/*单链表节点结构*/
typedef struct NodeType
{
char elem;
NodeType *next;
}Node;

/*双链表节点结构*/
typedef struct DNodeType
{
char elem;
DNodeType *next;
DNodeType *prev;
}DNode;

/*=============================================================================*/
/*
创建链表
*/
Node * CreateList(Node *head)
{
if(NULL == head)//分配头节点空间
head=(Node*)malloc(sizeof(Node)),
head->next=NULL;
Node *current=head , *temp;
char ch;
while(1)
{
cout<<"/n input elem:";
cin>>ch;
if('#' == ch)            /*#结束输入*/
break;
temp=(Node *) malloc ( sizeof(Node) );
temp->elem=ch;
temp->next=NULL;
current->next=temp;        /*当前节点的后驱指向新节点*/
current=temp;            /*当前节点为链表尾节点*/
}
return head;
}
/*=============================================================================*/
/*
输出链表
*/
void PrintList(Node *head)
{
Node * current=head->next;
cout<<"/n List are:";
while(NULL != current)
{
if(NULL != current->elem)
cout<<setw(5)<<current->elem;
current=current->next;
}
cout<<"/n";
}

/*=============================================================================*/

/*插入节点*/
Node *InsertNode(Node *head , char elem)
{
if( NULL == head || NULL == elem )
return head;
Node *current=head->next;    /*当前节点*/
Node *prev=head;            /*前驱节点*/
Node *temp;                    /*过渡节点*/

while(current)                /*移动至尾节点*/
{
prev=current;
current=current->next;
}
temp=(Node*) malloc( sizeof(Node) );
temp->elem=elem;
temp->next=NULL;
prev->next=temp;            /*尾节点的后驱指向新节点*/
return head;
}

/*=============================================================================*/
/*删除节点*/
Node *DeleteNode(Node *head,char elem)
{
if(NULL == head || NULL == elem)
return head;
if(NULL == head->next)
return head;
Node *prev,*current;
prev=head;
current=head->next;
while(current)
{
if(current->elem == elem)        /*匹配节点元素*/
{
prev->next=current->next;    /*前驱节点的后驱指向当前节点的下一个节点*/
free(current);                /*释放当前节点*/
return head;
}
prev=current;
current=current->next;            /*移动至下一个节点*/
}
return head;
}
/*=============================================================================*/

/*单链表逆置*/
Node *ReverseList(Node *head)
{
if(NULL == head)
return head;
if(NULL == head->next)
return head;
if(NULL == head->next->next)
return head;
Node *curr=head->next;  /*当前节点*/
head->next=NULL;
Node *temp;
while(curr)
{
temp=curr->next;    /*暂存下一个节点*/
/*把当前节点插入到head节点后*/
curr->next=head->next;
head->next=curr;
curr=temp;            /*移动至下一个节点*/
}
return head;
}
/*=============================================================================*/

/*求中间节点*/
Node * MiddleNode(Node *head)
{
if(NULL == head)
return head;
if(NULL == head->next)
return head->next;
Node *p1,*p2;
p1=head;
p2=head;
while(p2->next)
{
/*p2节点移动2个节点位置*/
p2=p2->next;
if(p2->next)                    /*判断p2后驱节点是否存在，存在则再移动一次*/
p2=p2->next;
/*p1节点移动1个节点位置*/
p1=p1->next;
}
return p1;
}

/*=============================================================================*/
/*合并有序单链表*/
Node * MergeList(Node * h1,Node * h2)
{
if(NULL == h1 || NULL == h2)
return h1;
if(NULL == h1->next )
return h2;
if(NULL == h2->next)
return h1;

Node * curr1,*curr2,*prev1,*temp;
prev1=h1;        /*链表1的前驱节点*/
curr1=h1->next;    /*链表1的当前节点*/
curr2=h2->next;    /*链表2的当前节点*/
temp=h2;
while(curr2)
{
while(curr1 && curr1->elem < curr2->elem)/*链表1指针移动至大或等于链表2当前元素的位置*/
prev1=curr1,curr1=curr1->next;

/*在链表1中插入链表2的当前元素*/
temp=curr2->next;/*暂存链表2的下一个节点*/
prev1->next=curr2;
curr2->next=curr1;
/*链表1移动至新节点*/
curr1=curr2;
/*链表2移动至下一个节点*/
curr2=temp;
}
return h1;

}
/*=============================================================================*/
/*创建双链表*/
DNode * DoubleList(DNode *head)
{
if(NULL == head)//分配头节点空间
head=(DNode*)malloc(sizeof(DNode)) , head->prev=NULL , head->next=NULL;

DNode *current=head , *temp;
char ch;
while(1)
{
cout<<"/n input elem:";
cin>>ch;
if('#' == ch)           /*#结束输入*/
break;
temp=(DNode *) malloc ( sizeof(DNode) );
temp->elem=ch;
temp->next=NULL;
current->next=temp;        /*当前节点的后驱指向新节点*/
temp->prev=current;        /*新节点的前驱指向当前节点*/
current=temp;            /*当前节点为链表尾节点*/
}
return head;
}

/*=============================================================================*/
/*输出双链表*/
void PrintDoubleList(DNode *head)
{
if(NULL == head)
return;
DNode * p;
p=head;
cout<<"/n DoubleList are:";
while(p->next)
{
p=p->next;
if(p->elem)
cout<<setw(5)<<p->elem;

}
cout<<"/n DoubleList are:";
while(p->prev)
{
if(p->elem)
cout<<setw(5)<<p->elem;
p=p->prev;
}
}

/*=============================================================================*/
/*创建循环链表*/
Node* CycleList(Node *head)
{
if(NULL == head)/*分配头节点空间*/
head=(Node*)malloc(sizeof(Node)),head->next=NULL;
Node *current=head , *temp;
char ch;
while(1)
{
cout<<"/n input elem:";
cin>>ch;
if('#' == ch)            /*#结束输入*/
break;
temp=(Node *) malloc ( sizeof(Node) );
temp->elem=ch;
temp->next=NULL;
current->next=temp;        /*当前节点的后驱指向新节点*/
current=temp;            /*当前节点为链表尾节点*/
}
current->next=head;            /*尾节点指向头节点*/
return head;
}
/*=============================================================================*/
/*判断链表是否有环(循环链表)*/
bool IsCycleList(Node *head)
{
if(NULL== head)
return false;
if(NULL == head->next)
return false;
Node *current=head->next;
while(current)
{
if(head == current->next)
return true;
current=current->next;
}
return false;
}
int main()
{
Node * head,*p;
Node * head2,*head3;
DNode * dHead;
char ch;
head = NULL;
head2=NULL;
head3=NULL;
dHead=NULL;

//head=(Node*) malloc ( sizeof( Node) );
//head->next = NULL;

//创建单链表
head=CreateList(head);
PrintList(head);

head2=CreateList(head2);
PrintList(head2);
//插入节点

cout<<"/n input elem to insert:";
cin>>ch;
InsertNode(head,ch);
PrintList(head);

//删除节点

cout<<"/n input elem to delete:";
cin>>ch;
DeleteNode(head,ch);
PrintList(head);
//单链表逆置

head=ReverseList(head);
cout<<"/n Reversed !";
PrintList(head);
//求中间节点

p=MiddleNode(head);
cout<<"/n Middle Node is:";
cout<<p->elem<<endl;

//合并有序单链表

MergeList(head,head2);
cout<<"/n Merged!";
PrintList(head);
//创建双链表

dHead=DoubleList(dHead);
PrintDoubleList(dHead);
/*创建循环链表并判断是否有环*/
head3=CycleList(head3);
cout<<IsCycleList(head3);
return 0;
}