Swift Tutorial - Swift Structures

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You can use structures to define custom types in Swift.

Structures give you a way of grouping related information together.

To define a Swift structure, use the struct keyword.

struct Rectangle {
    var x:Int = 0
    var y:Int = 0
    var width:Int = 0
    var height:Int = 0
}

Structure Instances

To use a structure type, you must create a new instance based on this definition.

struct Rectangle {
    var x:Int = 0
    var y:Int = 0
    var width:Int = 0
    var height:Int = 0
}

var rect = Rectangle()

Accessing Structure Properties

To access structure properties, you use dot syntax.

rect.x = 10
rect.y = 10
rect.width = 100
rect.height = 50

println("x: \(rect.x), y: \(rect.y), width: \(rect.width),height: \(rect.height)")

Structures are value types. This means members are copied and not passed by reference when the assignment statement is used.

Structure Functions

Swift structure types can have functions as part of their definition.

This means Swift structures not only can organize data but can define behavior.

The following code adds a function to a structure.

struct Rectangle {
    var x:Int = 0
    var y:Int = 0
    var width:Int = 0
    var height:Int = 0

    func description() -> String{
        return ("x: \(x), y: \(y), width: \(width), height: \(height)")
    }

}
var rect = Rectangle()
rect.x = 10
rect.y = 10
rect.width = 100
rect.height = 50

println(rect.description())

The code above generates the following result.

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