Emacs auto compelete paren, indent and new line - how to? - emacs

Question

In C - I want that when I type a { and then } emacs will insert a new line between them and then set the cursor in between them. For example:
int main() {
now I type } and the following happens:
int main()
{
//cursor is here
}
Edit: forgot to mention - I want emacs to know that when defining a function that it should do what was described above but when doing a for loop, or if statement for example I want it to do the following:
if (bla bla) {
type } and... :
if (bla bla) {
//cursor here
}

Answer 1

If you don't mind that the behaviour will be only almost, but not exactly the way you described it, there is a built-in way to do that. It's the auto-newline feature, that can be activated with the key combination C-c C-a or this line your .emacs:
(c-toggle-auto-newline 1)
The difference is that it will do the reformatting right after entering the opening brace {. When you finally enter the closing brace, it will indent it the right way, too.
You also need to set the right CC Mode style. The style "cc-mode" seems to define things the way you described it. You can activate it with the key combination C-c . and then choosing cc-mode, or the .emacs line
(c-set-style "cc-mode")
The c-mode functions are autoloaded and will therefore usually not be available while loading the .emacs file. Therefore you should wrap them in a hook for c-mode, like this
(add-hook 'c-mode-hook
(lambda ()
(c-toggle-auto-newline 1)
(c-set-style "cc-mode")))

Answer 2

As for the { stuff:
(define-minor-mode c-helpers-minor-mode
"This mode contains little helpers for C developement"
nil
""
'(((kbd "{") . insert-c-block-parentheses))
)
(defun insert-c-block-parentheses ()
(interactive)
(insert "{")
(newline)
(newline)
(insert "}")
(indent-for-tab-command)
(previous-line)
(indent-for-tab-command)
)
Paste the above into your .emacs. You can activate it with c-helpers-minor-mode.
Edit: The above inserts everything by just pressing {. The script below should do it if you type {}:
(defun insert-latex-brackets (opening closing) ; prototype function for all enclosing things
(interactive)
(insert opening)
(insert " ")
(insert closing)
(backward-char (+ 1 (length closing )))
)
(defun check-char-and-insert (char opening closing)
(interactive)
(if (equal char (char-to-string (char-before (point))))
(progn (delete-backward-char 1)
(insert-latex-brackets opening closing))
(insert char)
)
)
(local-set-key (kbd "}") 'check-char-and-insert)
One last note: You could try using yasnippet, which can be a real time saver used properly.