i have written this code for looking .txt file through directories and subdirectories inside that passed directory but it's not working..anyone suggest why?

you're giving it a non-existent directory

you're giving it a directory to which your program/login doesn't have permission to read

you're giving it a directory which has no ".txt" files

you're not running that program but some other program -- use full path to your program

Add more print statements, use more Basic debugging checklist