I want to hide the welcome screen.
My .emacs file:
(setq c-basic-offset 4) ; indents 4 chars
(setq tab-width 4) ; and 4 char wi
In Emacs 24, inhibit-splash-screen and inhibit-startup-message are alias for inhibit-startup-screen, so simply add (setq inhibit-startup-screen t) to your .emacs file will solve the problem.
Given that configuration, your startup buffer is now *scratch*, if you want to further change the default buffer, M-h v initial-buffer-choice will help.
Official document: http://www.gnu.org/software/emacs/manual/html_node/elisp/Startup-Summary.html