Sorting file content in descending order

I am new to C programming, especially in file I/O and I would like to know how can I sort my file content in descending order, according to the first numbers in each string (0001, 0002, ...).Attachment 16530
I have inserted the file I want to edit .
Thanks :D

The first thing would be to read the file into an array.

Can you do that?

Do you know about fopen / fgets / fclose functions?

Yes, I think so. I will leave what I did initially.Attachment 16531