Hello Everyone

Hope you will be fine and good.

First Question
Can anyone please provide me detailed tutorial on extern in ANSI C.

What they are?
Their purpose/benefits?
How to use extern with functions, structures, variables?
Everything other thing about externs.
Kindly give examples as many as you can.

Second Question

what is the default size of an enum.
can we change the default size of enums and how.
for example: if i want to use enums of 1 byte, how to do this?