need some help in software development with QuartusII example

Hi,

I am trying to modify the software part source code of a QuartusII example, CII_Starter_USB_API_V1 (CycloneII starter dev kit). I failed in building the C++ project with errors saying cannot find required header files. so does it mean I need those header files in my project folder?I am a newbie in C++, I don't understand because the original example works well, if those header files are not well included then how does the original example wotk?where can I find those header files?What can I do to build my version of the example? :confused:Hope some one could help me...

Thanks.