结构体实现单向链表

结构体实现单向链表

1.定义一个结构体

 

#include<iostream>
#include<cstdlib>
using namespace std ;
#define LEN (sizeof(struct student))
struct student{

  int num ;
  float score ;
  struct student *next ;

};
//定义全局变量，记录链表中所含节点个数
int n ;

 2.创建一个链表

 

/**
创建一个链表
*/
struct student *creat(void){
    struct student*p1,*p2,*head;
    n=0 ;
    p1=(struct student*)malloc(LEN) ;
    p2 = p1 ;
    head = NULL ;
    cin>>p1->num>>p1->score ;
    while(p1->num!=0)
    {
        n = n+1 ;
      if(n==1) head = p1 ;
      else p2->next = p1 ;

      p2 = p1 ;

      p1 = (struct student*)malloc(LEN) ;
      cin>>p1->num>>p1->score ;
      }
       p2->next = NULL ;
       return head ;

}

 3.输出链表

 

/**
输出链表
*/
void print(struct student *head)
{
    struct student *p0 ;
     p0 = head ;
     while(head!=NULL)
     {
         cout<<"学号"<<p0->num<<"  分数"<<p0->score<<endl ;
         p0 = p0->next ;
         if(p0==NULL) break ;
     }
}

 4.删除节点 

/**
删除节点  
*/
struct student *del(struct student *head,long num)
{
     struct student *p1,*p2;
     p1= head ;
     while(p1->num!=num)//找到了
     {    p2 = p1 ;
         p1=p1->next ;
         if(p1==NULL)
         {
             cout<<num<<"没找到"<<endl ;
             return head ;
         }
     }
     if(p1==head) head = head->next ;
     else{ p2->next = p1->next ;}
     cout<<"已删除"<<num<<endl ;
      free(p1) ;
      n = n-1 ;
      return head ;
}

 5.插入节点    

/**
插入节点  
*/
struct student *Insert(struct student *head,struct student *stu)
{
    struct student *p1,*p2 ;
    p1 = head ;
    if(head==NULL)
    {
        head = stu ;
    stu->next = NULL ;
    }else{
    while((p1->num<stu->num)&&(p1->next!=NULL))
    {
         p2 = p1 ;
         p1 = p1->next ;
     }
     if(p1->num>stu->num)
     {
         if(p1==head) head = stu;
         else  p2->next = stu ;

         stu->next = p1 ;

     }else
     {
      p1->next = stu ;
      stu ->next = NULL ;
     }
    }
     n = n+1 ;
     cout<<"已插入"<<endl ;
     return head ;
};

 6.对链表的综合操作

  

int main()
{
    struct student *head,*stu ;
    long del_num ;
    stu =(struct student*)malloc(LEN) ;
    cout<<"请输入！！！"<<endl;
    head = creat();
    print(head) ;
    cout<<"请输入要删除的元素!!!"<<endl ;
    cin>>del_num ;
    head = del(head,del_num) ;
    print(head) ;
    cout<<"请输入要插入的元素!!!"<<endl ;
    cin>>stu->num>>stu->score ;
    head = Insert(head,stu) ;
    print(head) ;


  return 0 ;

}