(add-hook 'c-mode-hook
          (lambda ()
            (local-set-key [f11] 'c-toggle-header-source)
            (local-set-key "\C-m"
                           (lambda ()
                             (interactive)
                             (c-indent-new-comment-line)
                             (c-indent-line-or-region)))
            (local-set-key [C-return] 'newline)))