I understand the overflows in java, but what is called underflows? and how can java handle it ?
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1Are you referring to integer underflow, or floating point underflow?Justin– Justin2011-04-25 20:37:59 +00:00Commented Apr 25, 2011 at 20:37
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Duplicate stackoverflow.com/questions/2154712/… ?DJClayworth– DJClayworth2011-04-25 20:38:49 +00:00Commented Apr 25, 2011 at 20:38
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The answer, as far as I know, is it doesn't. You'll get the exact same behavior as you would with a series of full adders.user684934– user6849342011-04-26 08:26:53 +00:00Commented Apr 26, 2011 at 8:26
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2 Answers
Underflow is the exact opposite of overflow.
int high = Integer.MAX_VALUE;
int overflow = high + 1;
int low = Integer.MIN_VALUE;
int underflow = low - 1;
And you handle it the same way: you make sure inputs are not going to put yourself in the range of over/underflow, and make the user aware of potential shortcomings. (Consider Math.abs(Integer.MIN_VALUE) == Integer.MIN_VALUE for instance.)
8 Comments
musiKk
To the best of my knowledge that's wrong (compare my answer). Could you cite sources for your claim?
corsiKa
how about the first result in Google for "integer underflow": cwe.mitre.org/data/definitions/191.html Note that floating point underflow and integer underflow are different notions, and the OP specifically asked for integer underflow.
MeBigFatGuy
i'd say subtracting one from MIN_VALuE is just overflow in the negative direction.
corsiKa
@MeBigFatGuy I've heard it called underflow from as long as I can remember. I have also heard it called "negative overflow." I cannot think of another definition of "integer underflow" though, and I think my handling of it is appropriate.
musiKk
@glowcoder: Fair enough. Given the clueless nature of the question I ignored the integer in the title and only concentrated on underflow as indicated in the question. I still think underflow per se is not the opposite of overflow. The downvote to my answer puts me in a rather lonesome position. If you edit your answer in some way, I'm able to remove my downvote to your answer. Please excuse my knee-jerk reaction.
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Quoting Wikipedia:
The term arithmetic underflow (or "floating point underflow", or just "underflow") is a condition in a computer program that can occur when the true result of a floating point operation is smaller in magnitude (that is, closer to zero) than the smallest value representable as a normal floating point number in the target datatype.
Others seem to think underflow is the exact opposite of overflow but I never saw that definition.
