#include <stdio.h>
#include <math.h>

struct infor                                                            /////建立一个结构体
{
    long num;
    char classify[2];
    char name[20];
    char author[30];
    float price;
    struct infor *next;
};

void main()
{
    float temp=sqrt(0);

    int n=0;
    char ch;
    struct infor *head;
    struct infor *p1, *p2;                                                       /////建立链表，没有错，已验证。

    p1=p2=(struct infor*)malloc(sizeof(struct infor));

    printf("\nPlease input num     :");
    scanf("%ld",&p1->num);
    ch=getchar();                                                                  ////吃回车，你懂的。  
    printf("\nPlease input classify:");
    scanf("%s",p1->classify);                                                      ////问题来了，如果这里我输入aa ，            
    ch=getchar();                                                                  
    printf("\nPlease input books'name :");                                                   
    scanf("%s",p1->name);                                                               这里再输入bb，你们猜会怎么样，系统显示，P1->classify='aabb';
    ch=getchar();                                                                        我就纳闷了，为什么我明明定义classify是2个字节的数组，它却能
    printf("\nPlease input author's name:");                                                无缘无故地多装2个字节？
    scanf("%s",p1->author);
    ch=getchar();
    printf("\nPlease input price of the book:");
    scanf("%f",&p1->price);
    ch=getchar();
    printf("--------------------------");
    head=0;

    while(p1->num!=0)
    {
        n++;
        if(n==1)
            head=p1;
        else
            p2->next=p1;

        p2=p1;
        p1=(struct infor *)malloc(sizeof(struct infor));
        printf("--------------------------");
        printf("\nPlease input num     :");
        scanf("%ld",&p1->num);
        ch=getchar();
        printf("\nPlease input classify:");
        scanf("%s",p1->classify);
        ch=getchar();
        printf("\nPlease input books'name :");
        scanf("%s",p1->name);
        ch=getchar();
        printf("\nPlease input author's name:");
        scanf("%s",p1->author);
        ch=getchar();
        printf("\nPlease input price of the book:");
        scanf("%f",&p1->price);
        ch=getchar();
    }
    p2->next=NULL;
   
}