Learning Swift™ Programming

Structs

Structs (which is short for structures) are copied when they’re passed around. Classes are passed around by reference. This means that you will never have the same instance of a struct. Conversely, you can have multiple instances of the same class.

Here is what classes and structs have in common:

■ Both define properties to store values.

■ Both define methods to provide functionality.

■ Both provide subscripts to give access to their values.

■ Both provide initializers to allow you to set up their initial state.

■ Both can be extended to provide additional functionality beyond a default implementation. (This is different from inheritance.)

■ Both have the ability to conform to protocols (which you will learn about in Chapter 8).

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