Re: installing GCC without internet connection ?
Fedora 11 is several years old, and no longer updated. I doubt yum would work anyway, unless you point it to an archive of the F11 repository.
As mentioned, GCC should be on the installation DVD if you have that, although that will be the initial release version rather than the latest bug-fixed version that would have been available before F11 was retired.
Your best bet is to upgrade to the current release, which is Fedora 17. If you download the installation DVD on another machine, you can install it with GCC included. There have been no updates to F17 GCC since F17's release.