# contains "string.h"
# contains "stdlib.h"
#define N 100 /* defines the total book capacity as 100*/
int Count = 0； /* Define a global variable to represent the number of books */
Struct book /* defines the structure type */
{
Int num/* serial number is an integer */
char name[40]； /* The title of the book is String */
Char author [20]; /* Author is a string */
char publish[50]； /* Publisher is the string */
Floating price; /* The price is a floating point */
};
Structure book list [n]; /* define variables of type struct book list N */
Void show_bookinformation (structured book list []); /* Declare the book information browsing function */
Void check_bookinformation (structured book list []); /* Declare book information inquiry function */
Void modify_bookinformation (structured book list []); /* Application for book information modification function */
Void delete_bookinformation (structured book list []); /* Declare the function of deleting book information */
Void reorder_bookinformation (structured book list []); /* Declare the book information sorting function */
Void buytotal (structured book list []); /* Function of declaring book purchase information */
void read()； /* Declare data read-in function */
Void input (); /* Declaration of book information entry function */
void open()； /* Open function of reporting data and information */
/* Main function */
void main()
{
int choice 1；
printf(" * ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ * \ n ")；
Printf(" * Welcome to the book sales management system * \ n ");
printf(" * ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ * \ n ")；
do
{
printf(" ## # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # ")； /* Display menu */
Printf ("function option: \ n");
Printf(" 1: book information entry \ n ");
Printf(" 2: book information browsing \ n ");
Printf(" 3: book information query \ n ");
Printf(" 4: book information modification \ n ");
Printf(" 5: book information deleted \ n ");
Printf(" 6: book information sorting \ n ");
Printf(" 7: book purchase \ n ");
Printf(" 0: exit the system \ n ");
printf(" ## # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # ")；
Printf ("\ tPlease select an operation:");
scanf("%d "，& ampchoice 1)；
Switch (select 1) /* Menu selection */
{
Case 1:
input()；
Break;
Case 2:
Show_bookinformation (list);
Break;
Case 3:
Check_bookinformation (list);
Break;
Case 4:
Modify_bookinformation (list);
Break;
Case 5:
Delete_bookinformation (list);
Break;
Case 6:
reorder _ book information(list)；
Break;
Case 7:
Buytotal (list);
Break;
Case 0:
Break;
}
}while (choice 1！ =0);
Printf ("Thank you! Welcome to use next time! \ n ")；
}
/* Open file function */
Invalid open ()
{
int I；
FILE * fp
if((fp=fopen("book.txt "，" Rb ")= = NULL)
{
Printf ("Unable to operate, no file information! ! ! \ n ")；
Exit (0);
}
for(I = 0； I & ltn；; i++)
{
if(fread(& amp； List[i], sizeof (structural book), 1, fp)==0)
{
Printf ("Data output failed! ! ! \ n ")；
Exit (0);
}
}
fclose(FP)；
}
/* Input file function */
Invalid read ()
{
int I；
FILE * fp
if((fp=fopen("book.txt "，" wr"))==NULL)
{
Printf ("\ nCannot open file! ! ! \ n ")；
Exit (0);
}
for(I = 0； I & ltn；; i++)
if(fwrite(& amp； List[i], sizeof (structural book), 1, fp)! = 1)
Printf ("File write error! ! ! \ n ")；
fclose(FP)；
}
/* Input function */
Invalid input ()
{
int i，k，j，t；
for(j = 0； List [j]. num！ =0; j++)
t = j+ 1；
for(I = 0； I & ltn；; i++)
{
Printf ("\ tPlease enter your book serial number:");
Scanf("\t%d ",& list [i]. num)；
Printf ("\ tPlease enter a title:");
scanf("\t%s "，list[i]。 Name);
Printf ("\ tPlease enter the author:");
scanf("\t%s "，list[i]。 Author);
Printf ("\ tPlease enter a publisher:");
scanf("\t%s "，list[i]。 Release);
Printf ("\ tPlease enter price:");
Scanf("\t%f ",& list [i]. Price);
fflush(stdin)；
Printf ("\ t \ nDo you want to continue typing? (1. is 2. No) ");
scanf("%d "，& ampk)；
If(k==2) is broken;
}
count = I+ 1；
read()；
}
/* Delete function */
Void delete_bookinformation (structured book list [])
{
int j，k，d，I = 0；
open()；
Printf ("Please enter the serial number of the book to be deleted: \ n");
scanf("%d "，& ampd)；
for(j = 0； List [j]. num！ =0; j++)
{
if(list[j].num==d)
{
for(k = j； List [k]. num！ =0; k++)
list[k]= list[k+ 1]；
i++；
}
}
If (i==0)
Printf ("The book serial number you entered is not available in the book sales system, please re-select and enter! ! ! \ n ")；
other
Count = Count- 1；
read()；
Printf ("Delete succeeded \ n");
}
/* Modify function */
Void modify_bookinformation (structured book list [])
{
int j，k=0，number
open()；
Printf ("\ tPlease enter the serial number of the book you want to modify:");
Scanf("%d ",&);
for(j = 0； List [j]. num！ =0; j++)
If (list[j].num = = number)
{
Printf ("\ n \ tPlease enter your revised book information! \ n \ n ")；
Printf ("\ tPlease enter the serial number of the book you want to modify:");
Scanf("%d ",& list [j]. num)；
Printf ("\ tPlease enter your modified title:");
Scanf("%s ",list [j]. Name);
Printf ("\ tPlease enter the modified author name:");
Scanf("%s ",list [j]. Author);
Printf ("\ tPlease enter your revision publisher:");
Scanf("%s ",list [j]. Release);
Printf ("\ tPlease enter the price of the revised book:");
Scanf("%f ",& list [j]. Price);
read()；
Printf ("\ nModified successfully! \ n ")；
k++；
}
If (k==0)
Printf ("\ n \ n \ tThe book to be modified cannot be found! !" );
}
/* Output function */
Void show_bookinformation (structured book list [])
{
int I；
open()；
printf(" \ n * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Printf ("book serial number \ tBook name \ t \ tAuthor name \ t \ tPublishing company \ t \ tBook price \ n");
for(I = 0； List [i]. num！ =0; i++)
{
printf(" % d \ t \ t % s \ t % s \ t \ t % s \ t % 6.2f \ n "，list[i]。 num，list[i]。 Name, list [i]. Author, list [i]. Publish, list [i]. Price);
}
}
/* Query function */
Voidcheck _ bookinformation (struct booklist [])/* Query book information */
{
int j，I，t，k = 0；
char c[20]，d[20]；
Printf ("Please enter the query method: \n 1. Query by heading 2. Query by author: \ n ");
scanf("%d "，& ampt)；
If (t== 1)
{
open()；
Printf ("Please enter the title of the book to be queried: \ n");
scanf("%s "，c)；
Printf ("\ n * * * * * * * * * The book information you want to query (according to the author's name) * * * * * * * * * * * * * * \ n");
Printf ("book serial number \ tBook name \ t \ tAuthor name \ t \ tPublishing company \ t \ tBook price \ n");
for(j = 0； List [j]. num！ =0; j++)
if(strcmp(c，list[j])。 name)==0)
{
printf(" % d \ t \ t % s \ t % s \ t \ t % s \ t % 6.2f \ n "，list[j]。 num，list[j]。 Name, list [j]. Author, list [j]. Publish, list [j]. Price);
k++；
}
If (k==0)
Printf ("\ nThe book information you want to query does not exist! ! ! \ n ")；
}
If (t==2)
{
open()；
Printf ("Please enter the name of the author to query: \ n");
scanf("%s "，d)；
Printf ("book serial number \ tBook name \ t \ tAuthor name \ t \ tPublishing company \ t \ tBook price \ n");
for(I = 0； List [i]. num！ =0; i++)
if(strcmp(d，list[i])。 Author) ==0)
{
printf(" % d \ t \ t % s \ t % s \ t \ t % s \ t % 6.2f \ n "，list[i]。 num，list[i]。 Name, list [i]. Author, list [i]. Publish, list [i]. Price);
k++；
}
If (k==0)
Printf ("\ nThe book information you want to query does not exist! ! ! \ n ")；
}
}
/* Sorting function */
Void reorder_bookinformation (structured book list [])
{
int i，j，a，k；
Structure book t;
FILE * fp
Charging temperature [40];
open()；
Printf ("\ nPlease select the sorting method \ n 1- Title (in alphabetical order) \ N2- Price (from highest to lowest) \ n");
scanf("%d "，& ampa)；
Switch (a)
{
Case 1:
for(I = 0； I< count-1; i++)
{ k = I；
for(j = I+ 1； J< counting; j++)
if(strcmp(list[k])。 Name, list [j]. Name) > 0) k = j;
If (k! =i)
{ strcpy(temp，list[i])。 Name);
Strcpy (list [i]). Name, list [k]. Name);
Strcpy (list [k]). Name, temporary);
}
}
if((fp=fopen("book.txt "，" w ")= = NULL)
{
Printf ("Can't open the file! \ n ")；
Exit (0);
}
Printf ("New sequence is: \ n");
Printf ("book serial number \ tBook name \ t \ tAuthor name \ t \ tPublishing company \ t \ tBook price \ n");
for(j = 0； J< counting; j++)
{
printf(" % d \ t \ t % s \ t % s \ t \ t % s \ t % 6.2f \ n "，list[j]。 num，list[j]。 Name, list [j]. Author, list [j]. Publish, list [j]. Price);
}
read()；
Break;
Case 2:
for(k = 0； List [k]. num！ =0; k++)
for(j = 0； List [j]. num！ =0; j++)
If(list[j]. price & lt list [j+ 1]. Price)
{ t = list[j]； list[j]= list[j+ 1]； list[j+ 1]= t； }
Printf ("book serial number \ tBook name \ t \ tAuthor name \ t \ tPublishing company \ t \ tBook price \ n");
for(j = 0； List [j]. num！ =0; j++)
{
printf(" % d \ t \ t % s \ t % s \ t \ t % s \ t % 6.2f \ n "，list[j]。 num，list[j]。 Name, list [j]. Author, list [j]. Publish, list [j]. Price);
k++；
}
read()；
Break;
}
}
/* Book purchase list */
Void buytotal (structural account book list [])
{
int k，m，n，q，r，t = 0；
float sum = 0；
char e[50]，f[50]，l[50]，o[50]，p[50]；
printf(" \ n * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \ n ")；
Printf ("\ nList of sample books of People's Posts and Telecommunications Publishing House \ n");
printf(" \ n * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \ n ")；
Printf ("Please enter the serial number of each book purchased (enter 0 to end): \ n");
scanf("%d "，& ampq)；
do
{
for(r = 0； r & ltn； r++)
{
if(q==list[r]。 Numbers)
{
sum=sum+list[r]。 Price;
t++；
}
}
scanf("%d "，& ampq)；
} while(q！ =0);
Printf ("Total number of books published: %d\n", t);
Printf ("book receiving unit:");
scanf("%s "，e)；
Printf ("publication basis:");
scanf("%s "，f)；
Printf ("price: %.2f\n", sum);
Printf ("Postal Code:");
scanf("%d "，& ampk)；
Printf ("shipping address:");
scanf("%s "，l)；
printf(" Tel:")；
scanf("%d "，& ampm)；
Printf ("creation date:");
scanf("%d "，& ampn)；
Printf ("freight company:");
scanf("%s "，o)；
printf(" reviewer:")；
scanf("%s "，p)；
}
This is for your reference. I don't know if it's ok. If so, share it with me.