How can I correctly filter data which is read from a file.csv and written on new_file.csv in a specific cell

Question

I am using C codes to convert PDF files which are automatically downloaded to the right folder, now require a way to not only find and compare the values and data but also to process it to a new file each month when the src files come in.

I am using Pdftotext for all my file formation and it seems to work beautifully for the given task.
https://code.sololearn.com/cf7e4Piqmphq/?ref=app