Need Advice in File Handling

[Gaurav Singh]

Hi. Recently I got a Task by my Teacher. He created a Simple PDF file named "myfile.pdf" and then protected this file with a Password i.e. "1234". Now He want me to open this File using a C/C++ Program instead of entering the password manually.. I have knowledge of File Handling but I have no idea.. How to do this..?? Someone please demonstrate with 2-3 lines of code that how to do it OR which function should I use..
THANKS !!! ^_^