C - How to display and delete data from a file.txt - c

Question

In the code below I'm trying to insert, display and delete data from a file.txt. I'm being able to insert successfully but my display function do not display correct and I don't know how to set up the logic to make the delete function. I would appreciate some help in changing the code so it can works. How can I set up the logic for it?
#include <stdio.h>
void menu() {
printf("Option 1 - Create a file and insert data:\n");
printf("Option 2 - Read file and display:\n");
printf("Option 3 - Delete content:\n");
printf("Option 4 - Exit:\n");
};
struct Book {
char title[256];
char author[256];
int pages;
int price;
};
void get() {
struct Book *book;
book = (struct Book*)malloc(sizeof(struct Book));
FILE *fPtr;
fPtr = fopen("file.txt", "w");
if (fPtr == NULL) {
printf("Fail creating file");
getch();
exit(1);
};
for (int i = 0; i < 1; i++) {
printf("Enter the book title:\n");
scanf("%s", &book[i].title);
fprintf(fPtr, "Title = %s", book[i].title);
printf("Enter the author of the book:\n");
scanf("%s", &book[i].author);
fprintf(fPtr, "Author = %s", book[i].author);
printf("Enter the number of pages:\n");
scanf("%d", &book[i].pages);
fprintf(fPtr, "Pages = %d", book[i].pages);
printf("Enter the price:\n");
scanf("%d", &book[i].price);
fprintf(fPtr, "Price = %d", book[i].price);
};
/*for (int i = 0; i < 1; i++) {
printf("%s\n", book[i].title);
printf("%s\n", book[i].author);
printf("%d\n", book[i].pages);
printf("%d\n", book[i].price);
};*/
fclose(fPtr);
};
void display() {
FILE *fPtr;
fPtr = fopen("file.txt", "r");
printf("The content of file are:\n", fPtr);
/*struct Book *book;
book = (struct Book*)malloc(sizeof(struct Book));
printf("%s %s %d %d", book.title, book.author, book.pages, book.price);*/
free(book);
fclose(fPtr);
}
int main()
{
int opt = 0;
int opt2 = 0;
int var = 0;
int validation = 0;
while (opt != 4) {
menu();
do
{
printf("Choose an option:\n");
validation = scanf_s("%d", &opt);
while (getchar() != '\n');
} while (validation != 1);
switch (opt) {
case 1:
get();
printf("Option 5 - Display data:\n");
printf("Option 6 - Delete:\n");
scanf("%d", &var);
if (var == 5) {
//FILE *fp1;
/*fp1 = fopen("file.txt", "r");*/
display();
}
else if (var == 6) {
printf("delete!");
}
break;
case 2:
printf("First insert data:\n");
break;
case 3:
printf("First insert data:\n");
break;
case 4:
return 0;
}
}
}

Answer 1

note : display() proposal 2
void display() {
FILE *fp;
fp = fopen("file.txt", "r");
struct Book book;
printf("%s %s %d %d", book.title, book.author, book.pages, book.price);
free(book);
fclose(fp);
}

Answer 2

I encourage you to rename Books to Book because that struct manages one book, not several.
About the command codes to enter, rather than 1 .. 4 what about 'c' for create, 'r' for read, 'd' for delete and 'e' for exit ?
Concerning get() :
you have a memory leak because the allocated Books is not freed. This allocation is useless, better to have struct Book book;
for (int i = 0; i < 1; i++) is useless and equivalent to int i = 0, do you really manages only 1 book ?
in your fprintf move the '\n' from the beginning to the end, else your file starts by an empty line and the last line is not ended
Is it necessary to prefix each data by its kind like Title = ? To read the file content is more complex with these prefixes
Concerning display() :
you do not read the content of the file, so difficult do display it :)
you allocate a Books, do not initialize it, but write its( uninitialized) fields
for (int i = 0; i < 1; i++) is useless and equivalent to int i = 0
you have a memory leak because the allocated Books is not freed. This allocation is useless, better to have struct Book book;
Concerning display() :
you do not read the content of the file, so difficult do display it :)
you allocate a Books, do not initialize it, but write its( uninitialized) fields
for (int i = 0; i < 1; i++) is useless and equivalent to int i = 0
you have a memory leak because the allocated Books is not freed. This allocation is useless, better to have struct Book book;
Concerning deleteStudentRecord() :
getNoOfRecords() is not defined, but currently it must return 1 because you manage only one book in the file
var is not defined, nor ptr
open file2 with "w", it is a new file
fread(&var, sizeof(struct student), 1, ptr) is wrong because it supposes a line has always sizeof(struct student) but this is not the case refering to get()
fcloseall() ??? just do fclose(ptr); and fclose(ptr2), rename them fpIn and fpOut or something like will make your code more readable

Answer 3

"get(); proposal 2"
void get() {
FILE *fPtr;
fPtr = fopen("file.txt", "w");
struct Book book;
if (fPtr == NULL) {
printf("Fail creating file");
getch();
exit(1);
};
printf("Enter the book title:\n");
scanf("%s", &book.title);
fprintf(fPtr, "%s", book.title);
printf("Enter the author of the book:\n");
scanf("%s", &book.author);
fprintf(fPtr, "%s", book.author);
printf("Enter the number of pages:\n");
scanf("%d", &book.pages);
fprintf(fPtr, "%d", book.pages);
printf("Enter the price:\n");
scanf("%d", &book.price);
fprintf(fPtr, "%d", book.price);
/*for (int i = 0; i < 1; i++) {
printf("%s\n", book[i].title);
printf("%s\n", book[i].author);
printf("%d\n", book[i].pages);
printf("%d\n", book[i].price);
};*/
fclose(fPtr);
};