How to handle division by zero in a language that doesn't support exceptions?
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How to handle division by zero in a language that doesn't support exceptions?
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Re: How to handle division by zero in a language that doesn't support exceptions?
#2For IEEE floating point, there is NaN and +/-Infinity which are raised when dividing by zero: http://grouper.ieee.org/groups/754/faq.html#exceptions
For integers that don't have NaN/infinity values the options are less clear. Note that languages with two's complement fixed width signed types like int32 have the same problem with INT32_MIN / -1, since the result is not representable as an int32.
Re: How to handle division by zero in a language that doesn't support exceptions?
#3Sounds like a new PHP in the making, someone even mentioned it in the link. I think it's the only language I have worked with that's so happy to chug along and ignore errors that arise in execution. And the exception system was just thrown on top of it in PHP5 as an afterthought. Ugh.
Re: How to handle division by zero in a language that doesn't support exceptions?
#4Thinking back to when I was a novice programmer, and the consequences of my mistakes when working on stuff that was probably over my head, "terminate with extreme prejudice" seems like the only acceptable option. No result and a call from a user seems better than a wrong result. Folks will use a tool for safety (personal or financial) critical tasks without really thinking about failure modes.
Things like pocket calculators, Excel, and even web forms, will cough up a lung and quit when they hit an exception. So I think that novices of today are probably amply familiar with this mode of operation, even before learning to program.
Re: How to handle division by zero in a language that doesn't support exceptions?
#5For IEEE floating point, there is NaN and +/-Infinity which are raised when dividing by zero: http://grouper.ieee.org/groups/754/faq.html#exceptions For integers that don't have NaN/infinity values the options are less clear. Note that languages with two's complement fixed width signed types like int32 have the same problem with INT32_MIN / -1, since the result is not representable as an int32.
Yeah, but they usually just say that the result is undefined. At least that's what C and C++ do. And it's useful for optimizers, because they can assume more about basic arithmetic in signed types and do some neat tricks.
Re: How to handle division by zero in a language that doesn't support exceptions?
#6[deleted]
Re: How to handle division by zero in a language that doesn't support exceptions?
#7For IEEE floating point, there is NaN and +/-Infinity which are raised when dividing by zero: http://grouper.ieee.org/groups/754/faq.html#exceptions For integers that don't have NaN/infinity values the options are less clear. Note that languages with two's complement fixed width signed types like int32 have the same problem with INT32_MIN / -1, since the result is not representable as an int32.
Yeah, but they usually just say that the result is undefined. At least that's what C and C++ do. And it's useful for optimizers, because they can assume more about basic arithmetic in signed types and do some neat tricks.
> Yeah, but they usually just say that the result is undefined.
Just to clarify, I think you're talking about the INT_MIN / -1 case?
I think that floating-point division by zero is defined in C and C++.
Re: How to handle division by zero in a language that doesn't support exceptions?
#8Sounds like a new PHP in the making, someone even mentioned it in the link. I think it's the only language I have worked with that's so happy to chug along and ignore errors that arise in execution. And the exception system was just thrown on top of it in PHP5 as an afterthought. Ugh.
I greatly dislike the language myself, but to be fair, it does allow the case where even a notice will terminate execution; and then to special-case functions that can safely fail with an @ prefix. Most people just turn all of that off with error_reporting()
Re: How to handle division by zero in a language that doesn't support exceptions?
#9For IEEE floating point, there is NaN and +/-Infinity which are raised when dividing by zero: http://grouper.ieee.org/groups/754/faq.html#exceptions For integers that don't have NaN/infinity values the options are less clear. Note that languages with two's complement fixed width signed types like int32 have the same problem with INT32_MIN / -1, since the result is not representable as an int32.
Yeah, but they usually just say that the result is undefined. At least that's what C and C++ do. And it's useful for optimizers, because they can assume more about basic arithmetic in signed types and do some neat tricks.
Calling it undefned is a cute meta-exception, but the compiler (or runtime) still does something when hitting that code.
Re: How to handle division by zero in a language that doesn't support exceptions?
#10It entirely depends on the application's role.
If it's used in a video game with no save slots, where a crash is just going to lose lots of progress, I'd rather attempt to keep going even if there's an error, but only in release builds. Crash in debug builds to try and alert the programmer.
If it's used to save important work, where the bad divide could lead to data corruption, it's probably better to crash than risk the corruption. Although if you have the capability to ask the user what to do, that would be ideal.
If it's to develop something that handles money or lives, or is eg deployed on a satellite, not even crashing is acceptable. In that case, I'd force the language to have the user test with something like Haskell's "Maybe". For instance:
if(result = x / y) { //x / y returns an object: maybe
z = result.get()
} // } else { handle division by zero case }