Class getter and setter in Swift

get_set.swift

import Darwin

class Circle {
    var radius: Double
    
    // contructor
    init(radius: Double) {
        self.radius = radius
    }
    
    // getter and setter method
    var area: Double {
        get {
            return M_PI * pow(radius, 2)
        }
        set (newArea) {
            radius = sqrt(newArea / M_PI)
        }
    }
}

// Create a new Circle instance
var myCircle = Circle(radius: 12)
myCircle.radius                     // 12.0
myCircle.area                       // 452.38934211693
myCircle.area = 1000                // set new area
myCircle.radius                     // new radius = 452.38934211693