What's the difference between "out" and "inout"?

[Unknown W. Brackets]

Image a state-based function that did not utilize a class for storing 
its state information.

bool do_something(in Stream s, inout int state);

Then you might do this:

int state = 0;
while (do_something(s, state))
    writefln("Current state: ", state, "\n");

This isn't the best example, I'm afraid, but it's the clearest one I can 
think of at the moment.  It's not needed every day, but it has definite 
uses.

I guess another option would be:

bool do_something(Stream s, in int previous_state, out new_state);

But that seems silly.

-[Unknown]


> Interesting, but why? What situations need this kind of behaviour?