PlanetarySystem.swift

import Foundation


class PlanetarySystem {

    let name:String
    let planets:[Planet]
    
    
    
    //computed properties -> curely braces -> always return something
    
    var randomPlanet:Planet? {

        if planets.isEmpty {
            return nil
        } else {
            //creating a variable to select a random planet
            let index = Int(arc4random_uniform(UInt32(planets.count)))
            return planets[index]
        }
        
    }
    
    
    
    init (name:String, planets:[Planet]){
        
        self.name = name
        self.planets = planets
    }
}