Quick Question about "Mod" operator

[dragonguy]

Try abs(negative number)

[James]

Try abs(negative number)

What?

[dragonguy]

Thats how to get it to work with negative numbers.

[HGHST]

Thanks, although I'll still probably never use it since I have no programming skills, it's useful to know what it is just in case. And thanks for the examples.

[Dynasoft]

Try abs(negative number)
Thats how to get it to work with negative numbers.

Actually no. abs(-2) is 2, when you'd expect it to be 30 using mod. Think directions: 0 = 32, -1 = 31, -2 = 30...

[Random]

Try abs(negative number)

*ignore*

I think it does, but like this:
-128 / 60 = -2
-128 mod 60 = -8

To wrap it positive IIRC you do this:
((number mod limit) + limit) mod limit)

Indeed. I don't find it very practical though. I've seen implementations where -128 mod 60 is 52. I find it rather annoying to have to write it the complicated way all the time, but then I guess I'm just lazy.

According to wikipedia there are three common ways to implement modulo. I suppose then it's down to luck which one you get with your development environment..

[Nifflas]

Euclidean definition ftw! I wish MMF2 used this.

[MuddyMole]

The mod function has heaps of uses - here's a couple more...

To determine if a number is odd or even:
if "Number" mod 2 = 0, then "Number" is even
if "Number" mod 2 = 1, then "Number" is odd


To find the difference between two angles:
((Angle1 - Angle2 + 540) mod 360) - 180

It essentially tells you whether to rotate clockwise or counter-clockwise, depending on whether the result is positive or negative.


To load a tile-based map from an array, using a fast loop:
XPosition = LoopIndex(">Fastloop<") mod DimX( ">Array<" )
YPosition = LoopIndex(">Fastloop<") / DimX( ">Array<" )