designated initializer：一個class至少一個
語法：
init(parameters){
}
便利初始化
convenience initializer：可有可無
語法：
convenience init(parameters){
}
import UIKit
class Vehicle {
var numberOfWheels = 0;
var description: String {
return "\(numberOfWheels) wheel(s)";
}
}
let vehicle = Vehicle();
print(vehicle.description);
class Bicycle:Vehicle{
override init(){
super.init();
numberOfWheels = 2;
}
}
let bicycle = Bicycle();
print("Bicycle:\(bicycle.description)");
class Hoverboard:Vehicle{
var color:String;
init(color:String) {
self.color = color;
super.init();
}
override var description: String{
return "\(super.description) in a beautiful \(color)";
}
}
let hoverboard = Hoverboard(color: "silver");
print("Hoverboard:\(hoverboard.description)");
//自動繼承
class Food{
var name:String;
init(name:String) {
self.name = name;
}
convenience init(){
self.init(name:"[noName]");
}
}
let nameMeat = Food(name: "Bacon");
let mysteryMeat = Food();
class RecipeIngredient:Food{
var quantity:Int;
init(name:String, quantity:Int){
self.quantity = quantity;
super.init(name: name);
}
override convenience init(name: String) {
self.init(name:name, quantity:1);
}
}
let oneMySteryItem = RecipeIngredient();
let oneBacon = RecipeIngredient(name: "Bancon");
let sixEggs = RecipeIngredient(name: "Eggs", quantity: 6);
