Re: Integer arithmetic in Java

[Joshua O'Madadhain]

On Tue, 4 Dec 2001, M Lang / S Railsback wrote:

> In de-bugging our first model in Java Swarm we finally figured out that:
> 
>       aFloat = (anInt) / (anotherInt);
> 
> gives aFloat a value truncated to a whole number. (We were doing
> movement calculations on a 2D grid with integer coordinates, trying to
> figure out why the critters ended up in the wrong places.)
> 
> Pardon my inexperience, but is that something that everybody knows? 

Well, given the fact that it tripped you, I'd hesitate to say that it's
something that "everyone knows", but it is a pretty standard feature of
most general-purpose programming languages that I've dealt with (C/C++,
Java, Pascal, ...).  Generally speaking, division of integral types gets
truncated to an integer, although there is some disagreement among
languages over whether -123.4 gets truncated to -123 or to -124.  You
could say that it's one of the classic computer arithmetic "gotchas".

Joshua O'Madadhain

 address@hidden Per Obscurius...www.ics.uci.edu/~jmadden
    Joshua Madden: Information Scientist, Musician, Philosopher-At-Tall
 It's that moment of dawning comprehension that I live for--Bill Watterson
My opinions are too rational and insightful to be those of any organization.





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