How does "immutable" work.

[Chris Cain]

In addition to what everyone else said, I think it's important to 
also say that, in general, you should _not_ cast away immutable 
or const like you did. As far as I'm concerned, it's a 
programming error. It's possible that future compilers might  
have immutable data stored in Read-Only Memory and forcing a 
change like this could potentially crash your program.