C document reading and writing plus linked list addition, deletion, modification and query

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define size sizeof(struct b)
struct b{
    int num;
    char name[10];
    int gs;
    struct b*next;
};
void read();//fscanf
void read1();//fgetc

void write();
void list();
void bianli();

void zengjia();
void shanchu();
void xiugai();

void bianlixie();

struct b*head=NULL;
int main()
{
    int c;

    
    do{
        printf(" Please input the operation :");
        scanf("%d",&c);
        switch(c){
            case 1:read();
            break;
            case 2:write();
            break;
            case 3:list();
            break;
            case 4:zengjia();
            break;
            case 5:shanchu();
            break;
            case 6:bianli();
            break;
            case 7:xiugai();
            break;
            case 0:
            break;

        }



    }while(c!=0);
    return 0;

}

void list()
{
    FILE*fp;
    int num;
    char name[10];
    int gs;
    struct b*p,*tail,*ptr;
    head=tail=NULL;
    fp=fopen("E:\\book.txt","r");
    if(fp==NULL)
    {
        printf(" File opening failure \n");
    }
    else{

        while(fscanf(fp, "%d%s%d", &num, name, &gs) != -1)
        {
            p=(struct b*)malloc(size);
            p->num=num;
            strcpy(p->name,name);
            p->gs=gs;
            p->next=NULL;
            if(head==NULL)
                head=p;
            else
                tail->next=p;
            tail=p;

            //printf("%d\t%s\t%d\n",num,name,gs);
        }   
    }
 

    fclose(fp);

}

void bianli()
{
    struct b*ptr;
    if(head==NULL){
        printf("No\n");
    }
    else{
        for(ptr=head;ptr!=NULL;ptr=ptr->next){
            printf("%d\t%s\t%d\n",ptr->num,ptr->name,ptr->gs);
        }
       
    }
    
    printf("\n");  
}
void write()
{
    FILE*fp;
    int num,gs;
    char name[10];
    int i,n;
    fp=fopen("E:\\book.txt","a+");
    if(fp==NULL)
    {
        printf(" File opening failure \n");
    }
    else
    {
        printf(" Please enter the number of books added :");
        scanf("%d",&n);
        printf(" Please enter the information of adding books ：\n");
        for(i=1;i<=n;i++){
            scanf("%d%s%d",&num,name,&gs);
            fprintf(fp,"\n%d\t%s\t%d",num,name,gs);

        }
       
    }
    fclose(fp);
}
void read1()
{
    FILE*fp;
    fp=fopen("E:\\book.txt","r");
    if(fp==NULL)
    {
        printf(" File opening failure \n");
    }
    else
    {
        char ch;
        printf(" Read information as ：\n");
        while(!feof(fp))
        {
            ch=fgetc(fp);
            putchar(ch);
        }
        fclose(fp);
    }

}
void read()
{
    FILE*fp;
    int num;
    char name[10];
    int gs;
    fp=fopen("E:\\book.txt","r");
    if(fp==NULL)
    {
        printf(" File opening failure \n");
    }
    else{
        while(fscanf(fp, "%d%s%d", &num, name, &gs) != -1)
        printf("%d\t%s\t%d\n",num,name,gs);   
    }
     printf("\n");  

    fclose(fp);
}

void zengjia()
{
    int n,i;
    int num,gs;
    char name[10];
    struct b*ptr,*L,*ptr1;

    printf(" Please enter the number of increases ：");
    scanf("%d",&n);
    for(i=0;i<n;i++){
        printf(" Please enter %d Information :",i+1);
        scanf("%d%s%d",&num,name,&gs);
        if(head==NULL){
            ptr=(struct b*)malloc(size);
            ptr->num=num;
            strcpy(ptr->name,name);
            ptr->gs=gs;
            head=ptr;
        }
        else{
            L=head;
            while(L->next!=NULL){
                L=L->next;
            }
            ptr1=(struct b*)malloc(size);
            ptr1->num=num;
            strcpy(ptr1->name,name);
            ptr1->gs=gs;
            ptr1->next=NULL;
            L->next=ptr1;

        }
    }
    bianlixie();
}


void shanchu()
{
    int num;
    printf(" Please enter the deletion book number ：");
    scanf("%d",&num);
    struct b*ptr1,*ptr2,*p;
    if(head->num==num&&head!=NULL)
    {
        ptr2=head;
        head=head->next;
        free(ptr2);

    }
    if(head==NULL)
    {
        printf(" No information \n");
    }
    ptr1=head;
    ptr2=head->next;
    while(ptr2!=NULL){
        if(ptr2->num==num){
            ptr1->next=ptr2->next;
            free(ptr2);
        }
        else
            ptr1=ptr2;
        ptr2=ptr1->next;
    }
    bianlixie();
}

void xiugai()
{
    int gs;
    int num;
    printf(" Please enter the revision number ：");
    scanf("%d",&num);
    printf(" Please enter the number of modifications as ：");
    scanf("%d",&gs);
    struct b*ptr;
    if(head==NULL){
        printf(" No information \n");
    }
    else{
        for(ptr=head;ptr!=NULL;ptr=ptr->next)
            {
                if(ptr->num==num)
                {
                    ptr->gs=gs;
                }  
            }
    }
    bianlixie();
}

void bianlixie()
{
    FILE*fp;
    int num,gs;
    char name[10];
    int i,n;
    struct b*ptr;
    fp=fopen("E:\\book.txt","w");
    if(fp==NULL){
        printf(" Open the failure \n");
    }
    else{

        for(ptr=head;ptr!=NULL;ptr=ptr->next){
                fprintf(fp,"%d\t%s\t%d\n",ptr->num,ptr->name,ptr->gs);
            }
    }
    fclose(fp);
}