# Differences between include "filename" and # include

1. # differences between include "FILENAME" and # include <FILENAME> For # include <FILENAME>, the compiler only searches for filename in the specified include file path, for more information, see tools> Options> projects and solutions> VC ++ directory. For # include "filename", the compiler first searches for filename in the path specified by filename (relative or absolute), and then searches for the specified include file path. 2. If file a contains filename. h or filename, how does the compiler handle filename. cpp? Replace filename. CPP is attached to filename. before the H file, attach the two to the front of a, but note that filename cannot be used directly in. the symbols (functions, global variables) in CPP must be declared before use (function declaration, extern Declaration)