Can you solve 3 for me? In my program the problems are probably swap and bubbleSort

Using modularization for abstract data, write a C program that provides, from the menu
user, the following domain features for book management:

1. Acquisition, from a file previously created by the student, of data from at least three books
   the. a line of the file contains the data of a book, more precisely Identifier, Author,
   Title, Publication Year, Price, Publisher, Number of Pages separated by the symbol
   “# as shown here
   or 1#Manzoni#PromessiSposi#1800#40#Bompiani#1000
   and 2# Manzoni #Programming#2000#30#Laterza#5000
   ii. the file name must be provided by the user on the keyboard
   iii. console data display
   iv. use a linked list data structure
2. Search for books that in an order relationship based on the criterion < Title, Publication Year,
   Publisher> represent the minimum value and maximum value
   the. with the same value of Title, the value of Publication Year is considered and, if applicable
   of equal value, the value of Publisher is considered
   ii. storage of the selected data in the MinMax.txt output file
3. Sorting of books with respect to an order relationship based on the criterion
   the. storage on the output file Sorted.txt
   ii. the direction of the sorting (ascending/descending) must be selected
   by the user from the keyboard. Make use of function pointers
   iii. the sorting algorithm can be chosen by the student.

I have already solved the first and second points, but the third gives problems in the sorting