Every block is a subprogram. The block in a do loop, the 
conditional block in an if or while statement. The subprogram blocks are 
everywhere in C; they're a basic construct of the language. I don't see 
why plain blocks woud be bad, ie neither conditional, nor loop. And I 
also consider a sane practice to restrict the scope of variables as much 
as it makes sense.

     It's just that there are two features that most C programmers never 
learn or quickly forget:

     1) blocks don't need to be conditional or loop,
     2) they can contain declarations.

     On the contrary, the ability to declare variables outside of a 
block, in the middle of instructions, like in C++ is a nonsense; it is 
an incitation to loose programming.

     I personnally re-discovered this very nice features a few years ago 
after having used the equivalent in Ada.

     Didier