How to count the number of lines in a file?

Question

C++ / C#

I'm trying to count the number of lines in the file (reading character by character), but the variable reads the characters 'H' constantly, there are a lot of them, although the file is only 3 lines of 3 characters each (text file), what could it be?

spoiler

Answer 1

The file_ptr variable is not initialized or the file was opened with an error.