Question

For C programming language, what does it mean when you have an exclamation mark after an equal sign? ie:

x=y;
y=!x;
x=!y;

Answer 1

My C is a bit rusty, but I believe the "=!" operator means "not equal to"

Answer 2

although, from what I've checked, "not equal to" is represented by "!="

Answer 3

I think it is bitwise operation.
For example,
x = 3 means x = 0011 in binary
y = !x means y = 1100 which results in y = 12.

Answer 4

The exclamation mark is not associated with the equal mark in this context. The line more accurately reads, x = !y, which means that whatever y is (true/false) set x to the opposite.

! returns the logical compliment of expr1: if expr1 evaluates to true (non-zero), it it returns 0; otherwise it returns 1.

Answer 5

eSpeX has nailed it.
\[\sqrt{4}\sqrt[2]{4}\]Although, in this context, 'complement' is the correct spelling; but I 'compliment' eSpeX on his answer ;-)

Answer 6

You are correct indeed, I missed that spelling error.

Answer 7

@dmorgan nice play of word
@eSpeX nice work as always