/*==================================================*/
/*=======链表的建立、输出、删除、插入等操作=========*/
/*==================================================*/
#include<stdio.h>
#include<malloc.h>
#define LEN sizeof(struct student)
/*--------------------------------------------------*/
struct student
{
long num;
float score;
struct student * next;
};
int n; /*n为全局变量,本文件模块中各函数均可使用它*/
/*--------------------------------------------------*/
void main()
{
struct student * creat(void);
void print(struct student *);
struct student * del(struct student * ,long);
struct student * insert(struct student * ,struct student *);
struct student * head, * stu;
long del_num;
printf("Input records:\n");
head=creat(); /*建立链表,返回头指针*/
print(head); /*输出全部节点*/
printf("\nInput the deleted number:");
scanf("%ld",&del_num); /*输入要删除的学号*/
while(del_num!=0)
{
head=del(head,del_num); /*删除后链表的头地址*/
print(head);
printf("Input the deleted number:");
scanf("%ld",&del_num);
}
printf("\nInput the inserted record:");
stu=(struct student *)malloc(LEN);
scanf("%ld,%f",&stu->num,&stu->score); /*输入要插入的结点*/
while(stu->num!=0)
{
head=insert(head,stu); /*插入一个结点,返回头结点地址*/
print(head); /*输出全部结点*/
printf("Input the inserted number:");
stu=(struct student *)malloc(LEN);
scanf("%ld,%f",&stu->num,&stu->score);
}
}
/*--------------------------------------------------*/
struct student * creat(void) /* 建立链表,此函数带回一个只想链表头的指针*/
{
struct student * head;
struct student * p1,* p2;
n=0;
p1=p2=(struct student * ) malloc(LEN); /*开辟一个新单元*/
scanf("%ld,%f",&p1->num,&p1->score);
head=NULL;
while(p1->num !=0)
{
n=n+1;
if(n==1)
head=p1;
else
p2->next =p1;
p2=p1;
p1=(struct student * ) malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);
}
p2->next =NULL;
return (head);
}
/*--------------------------------------------------*/
void print(struct student * head)
{
struct student * p;
printf("\nNow,these %d records are:\n",n);
p=head;
if(head!=NULL)
do
{
printf("%ld %5.1f\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) /*p1指向的不是所要找的结点,并且后面还有结点*/
{
p2=p1;
p1=p1->next; /*p1后移了一个结点*/
}
if(num==p1->num ) /*找到了要删的结点*/
{
if(p1==head)
head=p1->next ; /*若p1指向的是首结点,把第二个结点地址赋予head*/
else
p2->next =p1->next ; /*否则将下一结点地址赋给前一结点地址*/
printf("delete:%ld\n",num);
n=n-1;
}
else
printf("%ld not been found!\n",num); /*找不到该结点*/
end:;
return(head);
}
/*--------------------------------------------------*/
struct student * insert(struct student * head,struct student * stud)
{
struct student * p0,* p1,* p2;
p1=head; /*使p1指向第一个结点*/
p0=stud; /*p0指向要插入的结点*/
if(head==NULL) /*原来的链表是空表*/
{
head=p0; /*使p0指向的结点作为头结点*/
p0->next =NULL;
}
else
{
while((p0->num >p1->num) && (p1->next !=NULL))
{
p2=p1; /*使p2指向刚才p1指向的结点*/
p1=p1->next ; /*p1后移一个结点*/
}
if(p0->num <= p1->num)
{
if(head==p1)
head=p0; /*插到原来第一个结点之前*/
else
p2->next =p0; /*插到p2指向的结点之后*/
p0->next =p1;
}
else
{
p1->next =p0; /*插到最后的结点之后*/
p0->next =NULL;
}
}
n=n+1; /*结点数加1*/
return (head);
}