Calculating the difference of rotation states

Question

Is it possible to calculate the difference of rotation states? 359 and 0 should make 1 not 359.

Vulpes · Answer

OK, I'm clear now :) Try this revised version: using System; public struct RotationState { public readonly double Degrees; public RotationState (double degrees) { if (degrees { degrees = (-degrees) % 360; degrees = 360 - degrees; } Degrees = degrees % 360; } public static double operator -(RotationState r1, RotationState r2) { double diff1 = r1.Degrees - r2.Degrees; if (diff1 double diff2 = r2.Degrees - r1.Degrees; if (diff2 return Math.Min(diff1, diff2); } } class Test { static void Main() { var rs1 = new RotationState(0); var rs2 = new RotationState(359); double diff = rs1 - rs2; Console.WriteLine("The difference between {0} and {1} degrees is {2}", rs1.Degrees, rs2.Degrees, diff); rs1 = new RotationState(-12); rs2 = new RotationState(7); diff = rs1 - rs2; Console.WriteLine("The difference between {0} and {1} degrees is {2}", rs1.Degrees, rs2.Degrees, diff); Console.ReadKey(); } } The output should be: The difference between 0 and 359 degrees is 1 The difference between 348 and 7 degrees is 19

NameHere · Answer

Ok thank you that worked :)

NameHere · Answer

I want the shortest distance between the rotations (sorry couldn't find the right description for that what I want)

Vulpes · Answer

The difference between -12 and 7 is in fact 341. -12 is treated as 348, less 7, equals 341. Anyway, if these are not the answers you're expecting, then you should make it clear what you do want.

NameHere · Answer

The difference of -12 and 7 is 340, that's not right...

Vulpes · Answer

Are you sure you've copied it correctly? When I ran it, the output was: The difference between 0 and 359 degrees is 1 Of course if you reverse the operands so that you're subtracting 0 from 359 the result will be 359 because the subtraction method always works in a clockwise direction.

NameHere · Answer

Doesn't work. I'm getting 354 as difference and that shouldn't be possible.

Vulpes · Answer

It sounds like a good use for operator overloading: using System; public struct RotationState { public readonly double Degrees; public RotationState (double degrees) { if (degrees { degrees = (-degrees) % 360; degrees = 360 - degrees; } Degrees = degrees % 360; } public static double operator -(RotationState r1, RotationState r2) { double diff = r1.Degrees - r2.Degrees; if (diff return diff; } } class Test { static void Main() { var rs1 = new RotationState(0); var rs2 = new RotationState(359); double diff = rs1 - rs2; Console.WriteLine("The difference between {0} and {1} degrees is {2}", rs1.Degrees, rs2.Degrees, diff); Console.ReadKey(); } }

Calculating the difference of rotation states

Answers (8)