c++ include difference between quotes and brackets
In practice, the difference is in the location where the preprocessor
searches for the included file.
For #include <filename> the preprocessor searches in an implementation
dependent manner, normally in search directories pre-designated by the
compiler/IDE. This method is normally used to include standard library
header files.
For #include "filename" the preprocessor searches first in the same directory
as the file containing the directive, and then follows the search path used
for the #include <filename> form. This method is normally used to include
programmer-defined header files.