Re: A question about '=='' in C++!

On Sep 20, 10:15 pm, "Guofu Chen" <gc...@[EMAIL PROTECTED]
> wrote:
> Can anyone tell me the different between
> (1)
> int i, j;
> i = j ==1;

This statement invokes undefined behavior.  The value of j is
indeterminate and any attempt to evaluate it is prohibited.  If j were
somehow magically initialized to 0, then the statement says compare j
to 1 and assign the result (true or false) to i.  Since j is 0, the
compare is false and i is set to false (which is 0).
> cout << i;
> cout << j;
>
> and
> (2)
> int i, j;
> i = j = 1;

This says set i to the value of the expression j = 1.  The value of
that expression is the value assigned to j.

> cout << i;
> cout << j;
>
> Why the result of  (1) is
>
> 0 0
>
> while the result of (2) is
>
> 1 1
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