Swift – struct
A structure is generally used to define a light weight data object with small number of properties. A structure can contain properties of different datatypes.
struct keyword is used to define a structure in Swift programming language.
Syntax – struct in Swift
Following is the syntax of swift structure.
struct structureName {
// structure_body
} where
structureName is the name by which we shall reference this structure.
sturcture_body can contain constructs, properties and methods.
Example 1 – Swift Structure
Following is a simple example where the structure car contains properties like brand, name and seating capacity.
main.swift
struct car {
var brand: String
var name: String
var capacity: Int
init(brand: String, name: String, capacity: Int) {
self.brand = brand
self.name = name
self.capacity = capacity
}
}
let car1 = car(brand: "Hyundai", name: "Creta", capacity: 5)
print("Car details\n-----------")
print("Brand is \(car1.brand)")
print("Name is \(car1.name)")
print("Seating capacity is \(car1.capacity)") Output
Car details ----------- Brand is Hyundai Name is Creta Seating capacity is 5
Example 2 – Initialize some properties of the structure with default values
You can initialize some properties to default values in a structure.
main.swift
struct car {
var brand: String
var name: String
var capacity = 5
init(brand: String, name: String) {
self.brand = brand
self.name = name
}
}
let car1 = car(brand: "Hyundai", name: "Creta")
print("Car details\n-----------")
print("Brand is \(car1.brand)")
print("Name is \(car1.name)")
print("Seating capacity is \(car1.capacity)") Output
Car details ----------- Brand is Hyundai Name is Creta Seating capacity is 5
Example 3 – Swift Structure with Multiple init methods
This is kind of overloading methods. We can have multiple init methods with different sets of properties being initialized. But, you have to ensure that all the properties of the structure are being initialized.
main.swift
struct car {
var brand: String
var name: String
var capacity: Int
init(brand: String, name: String) {
self.brand = brand
self.name = name
self.capacity = 5
}
init(brand: String, name: String, capacity: Int) {
self.brand = brand
self.name = name
self.capacity = capacity
}
}
let car1 = car(brand: "Hyundai", name: "Creta")
print("Car details\n-----------")
print("Brand is \(car1.brand)")
print("Name is \(car1.name)")
print("Seating capacity is \(car1.capacity)")
let car2 = car(brand: "Toyota", name: "Innova", capacity: 7)
print("\nCar details\n-----------")
print("Brand is \(car2.brand)")
print("Name is \(car2.name)")
print("Seating capacity is \(car2.capacity)") Output
Car details ----------- Brand is Hyundai Name is Creta Seating capacity is 5 Car details ----------- Brand is Toyota Name is Innova Seating capacity is 7