Comparing function return value in C

I was making a program and I noticed that doing
if ((j = function()) == 20)
and
if (function() == 20)
behaved differently. Why is this? What's the difference between one and the other? The first one (the one that has a variable with the function return value) behaved as I thought it would, which is comparing the function return value with the constant. I don't know what the other one does. Thanks.

cretin

>>2
C is the first letter of cretin.

>>2
Fuck you.

They are the same except that j will be assigned a value in one case but not the other.

If you saw different behavior, then it's possible that function() has some static state and you get a different result each time you call it.

>>5
And this is why mutable state is considered harmful.

>>6
Because it's a side effect. Side effects are considered unholy in the jews of your jewish trained mathematicians that write code for a living.

* in the eyes of your jewish trained mathematicians*

>>6-7
I'm not sure which of you I hate more.

ONE WORD THE IMPLICIT COERCION OF NUMBER TYPES THREAD OVER

>>10
C has a number type? Is this an extension of the primitive types?

>>11
Yes, yes he did definitely say 'number type', and not 'number types'.

Anyway the proper standardese is arithmetic types.

>>10
Wow, you might be right!