How to write to the very beginning of a line?

Question

C++ / C#

Now I read the manual and realized that it’s not possible to write text to the very beginning of the file? I'm talking about fopen.
I have a file where I need to delete 4 lines starting from 2-5 and replace with other 2 lines.

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-ALLOW-CACHE:YES
#EXT-X-TARGETDURATION:11
далее текст тра-татата.

And get this

#EXTM3U
#EXT-X-TARGETDURATION:5
#EXT-X-PLAYLIST-TYPE:VOD
далее текст тра-татата.

I added the line to the end without any problems. But how to start or replace

Answer 1

Read the entire file into a variable. In the variable, change what you need. You write the entire variable to a file, deleting everything that was there before.