Difference between “using” and “include”?

[mbauman]

Let’s keep this discussion in one place:

What does `include` do?

There have been questions about this before, but so far none of them have provided an answer at the level of detail I have been looking for. My current understanding is that include is not a simple text substitution/replacement operation, which is how the C/C++ preprocessor works. Those languages simply substitute the line include("myfile.c") with the contents of myfile.c whenever such an include statement is encountered. Actually, in C/C++ the statement is #include "myfile.c" but you get the…