Swift开篇011->继承

class Cat: Animal {
// class body
}

super.someMethod()

super.someProperty

super[someIndex]

ovveride func eat() { ... }

// 重写 getter
ovveride var desc: String {
return super.desc + "detail"
}

// 重写属性观察器
override var currentSpeed: Double {
didSet {
gear = Int(currentSpeed / 10.0) + 1
}
}

final var

final func

final class func

final subscript

final class