script reading status gpio

Hello, I need a little code in C language in order to read a list of port on my raspberry pi. here is more detail : - the programme must read a list of pin(2,3,4 ect...) - when status for each pin is "0" the programme must run a shell command "touch /home/myfile1" - when status for each pin is "1" the programme must run a shell command "touch /home/myfile2" this programme will run in background on the raspberry pi , so it must use less ressource. please for sources so i can edit pin list and instruction for compil . best regards,