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Index › Programming Questions & Help › Syntax Questions › Quick question: is this "casting"

Phattee Junior Member Offline Posts: 89

Quick question: is this "casting"? Jan 5th, 2010, 10:44am   Quote: public class Vector3D {   public float x, y, z;   private float[] origVals;   public Vector3D() {   }   public Vector3D(float x, float y, float z){     this.x = x;     this.y = y;     this.z = z;     origVals = new float[]{x, y, z};   } I haven't seen that kind of notation before. I'm guessing that the float values in the { } are being converted into a float array. Is that correct?

Quark Senior Member Offline Posts: 411 UK

Re: Quick question: is this "casting"? Reply #1 - Jan 5th, 2010, 10:58am   Basically yes the line Code: origVals = new float[]{x, y, z}; causes an array of floats to be created. The size of the array will be 3 because we have provided 3 initial values inside the {} brackets. It is equivalent to Code: origVals = new float[3]; origVals[0] = x; origVals[1] = y; origVals[2] = z; This is not casting! Casting is the conversion of a variable from one data type to another e.g. Code: float f = 3.141589; int i = (int) f;  // i will have the value 3

Phattee Junior Member Offline Posts: 89	Re: Quick question: is this "casting"? Reply #2 - Jan 6th, 2010, 10:57am   Thanks! So is there any advantage to using origVals = new float[]{x, y, z}; instead of origVals = new float[3]; origVals[0] = x; origVals[1] = y; origVals[2] = z; or origVals = {x, y, z}; ?

PhiLho  YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: Quick question: is this "casting"? Reply #3 - Jan 6th, 2010, 1:53pm   Yes. The advantage over the first alternative is that it is much shorter, yet remaining readable. Moreover, with lot of values, incrementing the indexes is a chore. The advantage over the second alternative... is that it compiles! Java won't let you write that assignment, it is legal only at declaration time.

Phattee Junior Member Offline Posts: 89	Re: Quick question: is this "casting"? Reply #4 - Jan 7th, 2010, 10:57am   Thanks PhiLho & Quark, that was extremely informative. I've copied your replies verbatim onto my book