Do or loop until file exist

Hello,

I have no sucess, please can any post sample code and what include files i need to put, with a function, for loop until a file existt, then once exist open the file and read the first and third line.

Please do not post links to ther sites as i dont have  time for read tons of websites, like i made with no results

Jut a few lines of code, preferably with a function, and the includes

thanks

(PD. BASURA DE FORUM QUE EL EDITOR DE TEXTO PONE MAL LAS LETRAS LA HACE PEQUEÑAS)