why can't i put non-static chapter exam apportionment while loop?

you can, obviously, put non-static chapter loop:

for (int i = 0; ...

and i've beheld same thing switch statements well:

if ((int i = f()) != 0) ...

switch (int ch = stream.get()) ...

but i try same thing while loop:

while ((int ch = stream.get()) != -1) ...

the compiler (vc++ 9.0) does during all.

is agreeable behavior? there reason it?

edit: i found i this:

while (int ch = stream.get() != -1) ...

but since superiority rules, that's interpreted as:

while (int ch = (stream.get() != -1)) ...

which i want.