Re: [PD] div vs. / & i

On Fri, 6 Feb 2009, Jonathan Wilkes wrote:

But I just noticed while scrolling in a number box that they aren't the same when the dividend is negative. In the source for [div], I see this before doing the division: if (n1 < 0) n1 -= (n2-1); I feel like I'm missing something obvious. Why does [div] behave this way?

So that (x div y)*y + (x mod y) = x

So div is complementary to mod.

Also, int(x / y)*y + (x % y) = x

So / with i is complementary to %.

And div,mod behave the way that they do so that (x+y) mod y = x mod y (x+y) div y = (x div y) + 1

Whereas div with i and % do not, when x and x+y have different signs.

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