Newbie question

Hi.
ummm....I wondering
if I #include many many file in C++,
or import many many package in JAVA,
what will happen?

Will my file become bigger bigger?
even if got function never use?
Or will compiler auto remove all the never use function?

Thank u BBS!

lleeell e/g/in /g/ro e/bin/s lelin eroge gero\g/ro /gro lelski \g\ro/g/in ❝egriskel❞ \\guro ski lel jorge ``eroge`` jones lel groski grotato LE TANGASIMN EGI GWINGRIO``!''™ XDDSDDD