Second example is very readable using Allman style:<p><pre><code>    if( condition_a )
    {
         if( condition_b )
         {
             do_thing_a();
         } 
         else 
         {
             do_thing_b();
         }
    } 
    else 
    {
         do_something_else();
    }
</code></pre>
Editor space is free, why not use it.