Michiel Helvensteijn wrote:
Michiel Helvensteijn wrote:
Walter, surely this test shouldn't take more than a minute for you (or
anyone else with a D compiler installed).
Ok, ok. I'll do it. Here's the results:
----------------------------------
import std.stdio;
int main() {
writefln(8/3);
writefln(8/(-3));
writefln((-8)/3);
writefln((-8)/(-3));
writefln(8%3);
writefln(8%(-3));
writefln((-8)%3);
writefln((-8)%(-3));
return 0;
}
----------------------------------
outputs the following
----------
2
-2
-2
2
2
2
-2
-2
----------
So DMD uses truncated division. The quotient rounds towards zero and the
remainder has the same sign as the dividend. I've updated issue 3165 with
this information.
Hope that helps.
Thanks, Michiel. Here's what I have in TDPL. Is it 100% in sync with you?
=======================================
The multiplicative expressions are multiplication (\ccbox{a * b}),
division (\ccbox{a / b}), and remainder (\ccbox{a \% b}). They
operate on numeric types only. The result type is same as the type of
\ccbox{true ? a : b}.
i...@b@ is zero in \ccbox{a / b} or \ccbox{a \% b}, a hardware
exception is thrown. The sign\footnote{Sign, not signedness,
i.e.,~the sign of the actual value.} of \ccbox{a \% b} is always
the same as the sign o...@a@. That is, \ccbox{a \% b} is the closest
number to zero of the same sign o...@a@ that must be added t...@a@ to
make it divisible b...@b@. For example, \ccbox{-5 \% 2} and \ccbox{-5
\% -2} both yield~\cc{-1}.
\dee\ also defines modulus for floating-point numbers in the same way
as the IEEE~754 standard. When at least one of @a@ and @b@ is a
floating-point value in \cc{a \% b}, the result is the floating-point
number @r@ satisfying the relation \cc{a = b * n + r}, where @n@ is an
integer\footnote{``integer'' in the mathematical sense here} and @r@
is a positive number less than @b@'s absolute value.
=======================================
Thanks,
Andrei
