Learning Swift™ Programming

Structs Are Always Copied

Earlier we talked about how structs are always copied when they are passed around. Let’s take a look at an example that proves this, using the Point struct because it’s super simple:

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var point1 = Point(x:10, y:10)

Now you can create point2 and assign it to point1:

var point2 = point1

You modify point2:

point2.x = 20

Now point1 and point2 are different:

point1.x // 10point2.x // 20

If point1 and point2 were classes, you would not get different values because classes are passed by reference.