c - Replacing stdin within a piece of code -

i have piece of code uses stdin. when run program command-line pass location of wav file i.e. /users/username/desktop/music.wav.

the code written in c. stdin variable runs throughout 2 functions.

how replace stdin within code input of file directory , location?

in other words, how hard code '/users/username/desktop/music.wav' 2 different c functions.

i think looking freopen.

if understand correctly, read filename argv[1] , call freopen():

freopen(argv[1], "r", stdin);