Should includes go in header file?
Header files should #include the minimum header files necessary, and source files should also, though it’s not as important for source files. The source file will have the headers it #include s, and the headers they #include , and so on up to the maximum nesting depth.
Can we include .c file in header?
No, you always should avoid including a c file. A header file should contain only definitions/prototypes. A c file contains functions and should not be included.
How to include header files in a given source file?
It will work if the header is in a files folder in the same directory as the current source. If you’re trying to include a 3rd party library and not your own header, I’d suggest you to save the library headers in a particular path (say C:\\Library\\headers ). (If there are static libraries put them in some other path like C:\\Library\\lib ).
Is the local path relative to the CPP file?
The directory of your solution or makefile/project file is irrelevant, the local path is relative to the compilation unit, i.e. the cpp file. If that cpp file includes a header, that headers own includes are relative to itself, not the cpp file that included it. (It would be hell to manage if it were not).
What does it mean when a header file fails a test?
Warnings or errors regarding incomplete types or unknown types mean that the header file under test has some missing #include directives and/or missing forward declarations. Note well: Just because the test passes does not mean that the set of #include directives is sufficient, let alone minimal.
Where to save library headers in Visual Studio?
If you’re trying to include a 3rd party library and not your own header, I’d suggest you to save the library headers in a particular path (say C:\\Library\\headers ). (If there are static libraries put them in some other path like C:\\Library\\lib ). In your Visual Studio C++ Project, go to View > Other Windows > Property Manager.