#include <***.h> "***.h" differs from #include when introducing header files in C + +

Two cases are differentiated:

1, #include <> compiler will only go to the System file directory to find, can not find the error.

2, #include "" The compiler will look in the user directory first, then to the compiler set directory to find, and finally to the system files in the directory to find.

The above points of attention:

1, Situation 1 for the system self-lead file

2, Situation 2 for users to write their own header files

3, both cases can theoretically be used in the form of #include ", but the standard header file or system header file use its form will lead to reduced compilation efficiency

4. In the C++11 standard, you should use angle brackets when you include standard header or system header files provided by C + +; You should use double quotation marks when you include a custom header file

5, the general C in the header file is ***.h; C + + in the header file without. h

#include <***.h> "***.h" differs from #include when introducing header files in C + +