Parsing files in a directory?

Question

XML

Hello!
I haven’t written a program for a long time, tell me how best to parse a file in a directory (txt, xml) only 1 parameter is needed, which will later be written to a file with the found indicators.
There are about 2000 files.
Cpp php will do

Answer 1

Take and write. If xml - fasten a lib to work with XML. If TXT - parse what's inside.