03. The Dot Operator

When learning about objects like the robot in the Maze app, we used the dot operator to get access to the robot’s actions.

Similarly, when working with structs, we use the dot operator to get access to the struct’s properties. Here is all our code again for the Student, Point2D, and GeoLocation structs. We also have an instance of each struct. The instance names are ayush, characterPosition, and udacityCoordinates.

struct Student {
    let name: String
    var age: Int
    var school: String
}

struct Point2D {
    var x: Int = 0
    var y: Int = 0
}

struct GeoLocation {
    var latitude: Double = 0.0
    var longitude: Double = 0.0
}

var ayush = Student(name: "Ayush Saraswat", age: 19, school: "Udacity")
var characterPosition = Point2D(x: 10, y: 10)
let udacityCoordinates = GeoLocation(latitude: 37.400073, longitude: -122.108400)

To access their properties, we use the following syntax:

By using this syntax, we can retrieve or change property values for instances of structs.

Changing Struct Properties

For example, ayush is now a year older and studying at USC. So we should update his properties.

With the dot operator, these are quick changes. And, by clicking the eye icon in the right pane, you can see that the property values have updated correctly.

We cannot, however, change his name, because if we look back at the definition for the Student struct, name is declared as a constant.

QUESTION:

Can we change the property values of udacityCoordinates?

struct GeoLocation {
    var latitude: Double = 0.0
    var longitude: Double = 0.0
}

let udacityCoordinates = GeoLocation(latitude: 37.400073, longitude: -122.108400)