Say I have a header file named as "Complex.h"

On .cpp I want to include it. So I test it on following three ways.

  1. #include "Complex.h"
  2. #include ".\complex.h"
  3. #include "complex.h"


In all ways it works fine. So that means there is no any different between above three line?

When I use IDE to add classes to my applications, the header files are included as the second way.