Properties

import Foundation

class Person{
    var name = ""
}

class BlogPost {

    var fullTitle:String{
        if title != nil && author != nil {
            return title! + " by " + author!.name
        }
        else{
            return "No Title"
        }
    }

    var title:String?  //This is defined as NIL. The string is empty
    var body:String = "Welcome"
    var author:Person?  //empty
    var numberOfComments:Int = 0
}

let author = Person()
author.name = "Shihab"

let myPost = BlogPost()
myPost.author = author
myPost.title = "Swift for beginners"

print(myPost.fullTitle)