How can I handle non-negative mods?

Question

When I use the operator % in my Java programs, I keep getting negative answers. Example: -1%100 gives -1. While this is mathematically correct, I want to get the normal mathematical solution, or 99. In other words, I want to get the smallest positive integer solution. Is there any simple solution for this in Java (perhaps something I overlooked in Math? -- I can't find it)?

I also want to clarify that if there is something in the API that does this, a link would be awesome.

Answer 1

You can just do this?

int d = 100;

int x = -1 % d;
if (x < 0)
    x += d;

This should work for any positive d.

Answer 2

You can do the following

int myMod(int x, int modulo)
{
   return ((x % modulo) + modulo)  % modulo
}