How to convert an Integer or Float values into Degrees?

Question

For example:

float AngleAddition(float value)
{
   float angle = value + 90;
   return angle;  
 }

If the value passed is 340 to this method it should return a float of value 70 which is in degree. Since 340 + 90 = 360 + 70 (360 is nothing but 0 in degrees).

What is the expected behaviour for *negative* angles? what would the result be if it was -180 + 90 ? — Marc Gravell, Aug 13 '14 at 07:22
@MarcGravell's point is important, particularly for negative non-integral types where modulo *may* do something unexpected. — Bathsheba, Aug 13 '14 at 07:27
it would be -90 which is exactly I need ! The only thing is that, it should not be greater than +360 or -360 — Karthik, Aug 13 '14 at 07:28
-360 to +360 introduces degeneracy; for example, -90 is the same as +270. Are you sure you need this? — Bathsheba, Aug 13 '14 at 07:30
@Bathsheba A just question ! For now am passing only positive values, may be it would be a problem in future implementation — Karthik, Aug 13 '14 at 07:54

score 2 · Answer 1 · edited May 23 '17 at 12:11

2

You should use the modulo operator with the 360 value.

public float AngleAddition(float angle, float value)
{
   return (angle + value)%360;  
}

The modulo operator should work for float or double, just keep in mind the limitations of numeric representation. See this question for a case study.

edited May 23 '17 at 12:11

Community

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answered Aug 13 '14 at 07:12

Zoltán Tamási

12,249
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Sriram Sakthivel · Answer 2 · 2014-08-13T19:24:58.597

0

private float AngleAddition(float value)
{
   return (value + 90) % 360;  
}

edited Aug 13 '14 at 19:24

answered Aug 13 '14 at 07:10

Sriram Sakthivel

72,067
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I'm not sure either, but *are you confident* this works for floating point types? Not sure about the value 90 either but that seems to be what the OP wants. – Bathsheba Aug 13 '14 at 07:12
@Bathsheba Just tested with sample input OP provided, If not cast it to integer it will work. 90 is one quarter of 360 degree. That's what OP asks. – Sriram Sakthivel Aug 13 '14 at 07:13
You ought to verify 360.1 for example. – Bathsheba Aug 13 '14 at 07:14
@Bathsheba Just tested, it returns `0.1000061`. Rounding it as integer depends upon op's need. – Sriram Sakthivel Aug 13 '14 at 07:16
Why %90? You would not expect 180+90 to result in zero. You would expect 270. Also: what happened to the "addition" part of the question? – Marc Gravell Aug 13 '14 at 07:21
@MarcGravell Question asks for input `340` should return `70`. If you ask as degrees It would still be `340` isn't it? – Sriram Sakthivel Aug 13 '14 at 07:23
no, the OP asks that 340 **plus 90**, i.e. 430 - results in 70. The kep point being that 360 is a complete circle, so 430 degrees is the same direction as 70 degrees. – Marc Gravell Aug 13 '14 at 07:24
1

I just understand the question. Thanks for making it clear. I'll update my answer. – Sriram Sakthivel Aug 13 '14 at 07:25

How to convert an Integer or Float values into Degrees?

2 Answers2