class Circle {
var radius = 12.5
var area: String {
return "矩形半径 \(radius) "
}
}
// 继承超类 Circle
class Rectangle: Circle {
var print = 7
override var area: String {
return super.area + " ,但现在被重写为 \(print)"
}
}
let rect = Rectangle()
rect.radius = 25.0
rect.print = 3
print("Radius \(rect.area)")