C 動態鏈表的建立，輸出，刪除，插入

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動態鏈表的建立，輸出，刪除，插入

#include<stdio.h>

#include<malloc.h>

#include<stdlib.h>

#define NULL 0

#define LEN sizeof(struct student)

struct student

{

    long num;

    float score;

    struct student*next;

};

 int n;/*n為全域變數*/

 

struct student *creat()

{

    struct student*p1,*p2,*head;

    n=0;

    p1=p2=(structstudent *)malloc(LEN);

    scanf("%ld,%f",&p1->num,&p1->score);

    head=NULL;

    while(p1->num!=0)

    {

       n=n+1;

       if(n==1)

              head=p1;

       elsep2->next=p1;

       p2=p1;

       p1=(structstudent *)malloc(LEN);

       scanf("%ld,%f",&p1->num,&p1->score);

    }

    p2->next=NULL;

    return (head);

}

 

 

void print(struct student *head)

{

    struct student*p;

    printf("\nThese  records are:\n");

    p=head;

    if(head!=NULL)

       do

       {

              printf("%ld,%f\n",p->num,p->score );

              p=p->next;

       }while(p!=NULL);

}

 

 

struct student *del(struct student *head,long num)

 {

     struct student *p1,*p2;

 

    if(head==NULL)

     {printf("\nlist null!\n");goto end;}

 

     p1=head;

     

     while(num!=p1->num&&p1->next!=NULL)

     {

        p2=p1; p1=p1->next;

     }

     

     if(num==p1->num)

     {

        if(p1==head)head=p1->next;

        else p2->next=p1->next;

        printf("delete:%ld\n",num);

        n=n-1;

     }

     else printf("%d not beenfound!\n",num);

end:;

     return(head);

 }

 

 struct student*insert(struct student *head,struct student *stud)

 {

     struct student *p0,*p1,*p2;

     p1=head;

     p0=stud;

     if(head==NULL)

     {

        head=p0;p0->next=NULL;

     }

     else

     {

        while((p0->num>p1->num)&&(p1->next!=NULL))

        {

               p2=p1;

               p1=p1->next;

        }

 

        if(p0->num<=p1->num)     //和上面的if矛盾，不對

               {

                      if(head==p1)head=p0;

                      else p2->next=p0;

                      p0->next=p1;

               }

               else

               {p1->next=p0;p0->next=NULL;}

     }

        n=n+1;

        return(head);

 }

                      

 

void main()

{

    struct student*head ,stu;

    long del_num;

    printf("inputrecords:\n");

    head=creat();

    print(head);

 

    printf("\ninputthe deleted number:");

    scanf("%ld",&del_num);

    head=del(head,del_num);

    print(head);

 

    printf("\ninputthe inserted record:");

    scanf("%d,%f",&stu.num,&stu.score);

    head=insert(head,&stu);

    print(head);

}