Anyone knows how I can solve this problem? TY
This message comes from the compiler, not the IDE.
The
compiler tells you that it cannot find the file - this has nothing to do with whether you see this file in the
IDE. So - in your project options, setup the compiler's include directory as needed. This will pass the path to your header file(s) to the compiler's command line. If needed, do the same with the linker so that the linker can find the library/libraries you need to link against.
BTW: Next time please search the forums before asking. This has been answered a million times.
In addition: This is also a quite basic question. If you learn developing applications in C/C++ I recommend you really try the command line first (not using any IDE) to learn the basics about how a compiler/linker works. This will help you a lot in setting up your projects using a(ny) IDE.