链表操作

#include<iostream>
#include<malloc.h>
using namespace std;

typedef struct hNode
{
 char data;
 struct hNode *next;
}LinkList;

//初始化单链表h
void InitList(LinkList *&h)
{
 h= (LinkList *)malloc(sizeof(LinkList));
 h->next = NULL;
}

//尾插法插入元素
void CreateListR(LinkList *&h)
{
 LinkList *s,*r;
 char a[5]={'a','b','c','d','e'};
 int i;
 h=(LinkList *)malloc(sizeof(LinkList));
 r=h;
 for(i=0;i<5;i++)                          //尾插法把元素插入链表
 {
  s=(LinkList *)malloc(sizeof(LinkList));
  s->data = a[i];
  r->next = s;
  r=s;
 }
 r->next=NULL;
}

//输出单链表
void DispList(LinkList *h)
{
 LinkList *p = h->next;
 while(p!=NULL)
 {
  cout<<p->data<<" ";
  p=p->next;
 }
}

//输出单链表的长度
int Listlength(LinkList *h)
{
 int n=0;
 LinkList *p = h->next;
 while(p!=NULL)
 {
  n++;
  p=p->next;
 }
 cout<<"the list's length is "<<n<<endl;
 return 0;
}

//判断单链表是否为空
bool ListEmpty(LinkList *h)
{
 if(h->next == NULL)
 {
  cout<<"List is empty~!";
       return false;
 }
 else
 {
  cout<<"List is not empty";
  return true;
 }
 cout<<endl;
}

//输出单链表的第三个元素
char GetElem(LinkList *h)
{
 int j=0;
 char three;
 LinkList *p = h;
 while(j<3)
 {
  j++;
  p=p->next;
 }
 if(p==NULL)
  cout<<"不存在第三个元素"<<endl;
 else
 {
  three = p->data;
  cout<<"the third is "<<three<<endl;
 }
 return 0;
}

//输出元素a的位置
int LocateElem(LinkList *h)
{
 int i=1;
 char a='a';
        LinkList *p = h->next;            //指针指向第一个节点
 while(p!=NULL&&p->data!=a)
 {
  p=p->next;
  i++;
 }
 if(p==NULL)
  cout<<"不存在元素a"<<endl;
 else
  cout<<"a is the "<<i<<" in the list"<<endl;
  return 0;
}

//在第四个元素位置上插入元素f
bool ListInsert(LinkList *&h)
{
 int j=0;
 char f='f';
 LinkList *p =h,*s;
 while(j<3 && p!=NULL)
 {
  j++;
  p=p->next;
 }
 if(p == NULL)
 {
  cout<<"List is empty"<<endl;
  return false;
 }
 else                    //增加一个数据域为f的节点，插入链表
 {
  s=(LinkList *)malloc(sizeof(LinkList));
  s->data = f;
  s->next = p->next;
  p->next = s;
  cout<<"Insert done"<<endl;
  return true;
 }
}

//删除第三个元素
bool ListDelete(LinkList *&h)
{
 int j=0;
 char third;
 LinkList *p = h,*q;
 while(j<2 && p!=NULL)
 {
  j++;
  p = p->next;
 }
 if(p == NULL)
 {
  cout<<"List is empty"<<endl;
  return false;
 }
 else
 {
  q = p->next;
  if(q == NULL)
  {
   cout<<"Error"<<endl;
   return false;
  }
  else                         //删除第三个节点，原来第二个和第四个节点相连
  {
   third = q->data;
   p->next = q->next;
   delete(q);
   cout<<"deleted done"<<endl;
   return true;   
  }
 }
}

 
 //释放单链表
void DistoryList(LinkList *&h)
 {
  LinkList *pre = h,*p = pre->next;
  while(p!= NULL)
  {
   delete(pre);
   pre=p;
   p=pre->next;
  }
  delete(pre);
  cout<<"List gone"<<endl;
 }
 
 int main()
 {
  LinkList *h=NULL;
  int n;
  cout<<"~~ 第一次操作需先进行初始化 ~~"<<endl;
  cout<<" 请选择以下操作："<<endl;
  cout<<"1、初始化顺序表 "<<endl;
  cout<<"2、尾插法插入元素"<<endl;
  cout<<"3、输出链表中的元素"<<endl;
  cout<<"4、输出链表的长度"<<endl;
  cout<<"5、判断链表是否为空 "<<endl;
  cout<<"6、输出单链表的第三个元素"<<endl;
  cout<<"7、输出第一个值为a的元素的位置 "<<endl;
  cout<<"8、在第四个元素位置上插入f"<<endl;
  cout<<"9、删除第三个元素"<<endl;
  cout<<"10、释放链表"<<endl;
  cout<<"按其它键退出"<<endl;
  while(cin>>n)
  {
   switch(n)
   {
   case 1: 
    InitList(h);
    cout<<"You can continue."<<endl;break;
   case 2:
    CreateListR(h);
    cout<<"List have been created."<<endl;break;
   case 3:
    DispList(h);
    cout<<endl;break;
   case 4:
    Listlength(h);break;
   case 5:
    ListEmpty(h);
    cout<<endl;break;
   case 6:
    GetElem(h);break;
   case 7:
    LocateElem(h);break;
   case 8:
    ListInsert(h);break;
   case 9:
       ListDelete(h);break;
   case 10:
    DistoryList(h);break;
   default:
    exit(0);
   }
  }
  return 0;
  
 }