title: vim: smartindent (or cindent) is activated but does not work
body: <p>Vim is not autoindenting the C source files I am working on, although it claims both the autoindent and cindent options are enabled when I type the
  :set
  command.
  Nothing is happening when I type in some code. For instance writing</p>
  
  <pre><code>int main()
  {
  return 0;
  }
  </code></pre>
  
  <p>the "return 0;" statement stays on the left.
  However if I type the "=G" command, my file gets indented.</p>
  
  <p>Here is my config:</p>
  
  <ul>
  <li>ubuntu 13.04</li>
  <li>vim 7.3.547 + vim-scripts</li>
  </ul>
  
  <p>vimrc is splitted into /etc/vim/vimrc and ~/.vimrc. The concatanated content is as follow:</p>
  
  <pre><code>runtime! debian.vim
  
  if has("syntax")
    syntax on
  endif
  
  set background=dark
  
  " Uncomment the following to have Vim jump to the last position when
  " reopening a file
  if has("autocmd")
    au BufReadPost * if line("'\"") &gt; 1 &amp;&amp; line("'\"") &lt;= line("$") | exe "normal! g'\"" | endif
  endif
  
  if has("autocmd")
    filetype plugin indent on
  endif
  
  set showcmd
  set showmatch
  
  if filereadable("/etc/vim/vimrc.local")
    source /etc/vim/vimrc.local
  endif
  
  """"""" now this is ~/.vimrc """""
  
  set runtimepath+=,/usr/share/vim-scripts
  
  set autoindent
  set noexpandtab                                                                 
  
  " create ~&lt;file&gt; when saving modifications to &lt;file&gt;
  set backup
  
  " preserve source's format when pasting
  set paste
  
  " disable mouse usage
  set mouse=
  
  " colors
  set t_Co=256
  colorscheme mustang
  
  set hlsearch
  
  set number
  
  set cursorline
  
  if has("statusline")
     hi User1 ctermbg=red cterm=bold,reverse
     hi User2 ctermbg=darkblue cterm=bold,reverse
     hi User3 ctermbg=darkred cterm=bold,reverse
     hi User4 ctermbg=brown cterm=bold,reverse
  
     set laststatus=2
     set statusline=%h%f\ %y\ %1*%r%*%1*%m%*%=[col:%2*%c%*]\ [line:%3*%.6l%*/%4*%.6L%*\ -\ %p%%]
  endif
  
  set spellsuggest=5
  
  match Error /\s\+$/
  </code></pre>
  
  <p>Do you have any idea ?</p>
  
  <p>Thank you very much for your help.</p>
  
  <p>Pierre</p>