Imbaud Pierre <[EMAIL PROTECTED]> writes:
> integer division and modulo gives different results in c and python,
> when negative numbers
> are involved. take gdb as a widely available c interpreter
> print -2 /3
> 0 for c, -1 for python.
> more amazing, modulos of negative number give negative values! (in c).
> from an algebraic point of view, python seems right, but I thought
> python conformity to the underlying c compiler was a strong commitment,
AIUI the C standard is silent on the issue, and hence the C behavior is
implementation-dependent. Anyway back in 2000 I found and fixed a
Y2K-related problem in an open-source C program (xvtdl) which was down
to precisely this misbehavior. While diagnosing the problem I
implemented the algorithm in Python for test purposes, and was led
astray for a while by the fact that it *didn't* fail!
A: 42
Q: What multiple of 7 did I add to the critical expression in the Zeller
algorithm so it would remain nonnegative for the next few centuries?
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Mark Jackson - http://www.alumni.caltech.edu/~mjackson
People who write obscurely are either unskilled in writing
or up to mischief. - Sir Peter Medawar
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