what does this line of code do?

What does this line of code do?

Code:

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#define        FL_FLY        (1<<0);

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I'm just not sure what the << is for. If you are wondering its from a game engine, I don't know if that is relevant or not.

>#define FL_FLY (1<<0);

defines FL_FLY as 1

the simi colon shouldn't be there though, it could lead to problems, and things like this

int p = FL_FLY
note the lack of a semi colon, this makes the code less readable, and more confusing

and printf("%d", FL_FLY); // is illegal because of the semi colon in the define


the '<<' shifts the bits to the left the specified number of times in this case '0'.
do a search for 'bit manipulation', or 'bit shifting', ect...

And >> is for right shifting, ~ for negation, ^ for xor, & for and, | for or'ing... etc :p