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    <h3>To Normalised to [0,360):</h3> <p>(I.e. a half open range)</p> <p>Use the modulus operator to perform "get division remainder":</p> <pre><code>361 % 360 </code></pre> <p>will be 1.</p> <p>In C/C++/... style languages this would be</p> <pre><code>gundeg %= 360 </code></pre> <p>Note (thanks to a comment): if gundeg is a floating point type you will need to either use a library function, in C/C++: fmod, or do it yourself (.NET):</p> <pre><code>double FMod(double a, double b) { return a - Math.floor(a / b) * b; } </code></pre> <h3>Which Way To Turn?</h3> <p>Which ever way is shorter (and if turn is 180°, then the answer is arbitrary), in C#, and assuming direction is measured anti-clockwise</p> <pre><code>TurnDirection WhichWayToTurn(double currentDirection, double targetDirection) { Debug.Assert(currentDirection &gt;= 0.0 &amp;&amp; currentDirection &lt; 360.0 &amp;&amp; targetDirection &gt;= 0.0 &amp;&amp; targetDirection &lt; 360.0); var diff = targetDirection - currentDirection ; if (Math.Abs(diff) &lt;= FloatEpsilon) { return TurnDirection.None; } else if (diff &gt; 0.0) { return TurnDirection.AntiClockwise; } else { return TurnDirection.Clockwise; } } </code></pre> <p><strong>NB.</strong> This requires testing.</p> <p>Note use of assert to confirm pre-condition of normalised angles, and I use an assert because this is an internal function that should not be receiving unverified data. If this were a generally reusable function the argument check should throw an exception or return an error (depending on language).</p> <p>Also note. to work out things like this there is nothing better than a pencil and paper (my initial version was wrong because I was mixing up using (-180,180] and [0,360).</p>
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    1. POGetting the computer to realise 360 degrees = 0 degrees, rotating a gun turret
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    1. COThis seems like best solution. :)
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      1. USArnis Lapsa
    2. COBut how do you use this to determine which way to turn?
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      1. USJoshBerke
    3. CONote that if you're using floating point angles (as most people do) you need to use a floating point modulus. In C/C++ this is the fmod() function, or in C# it's Math.IEEERemainder().
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