4.3 A Swift Playground Example

Perhaps the simplest of examples in any programming language (that at least does something tangible) is to write some code to output a single line of text. Swift is no exception to this rule so, within the playground window, begin adding another line of Swift code so that it reads as follows:

import UIKit

 

var str = "Hello, playground"

 

print("Welcome to Swift")

All that the additional line of code does is make a call to the built-in Swift print function which takes as a parameter a string of characters to be displayed on the console. Those familiar with other programming languages will note the absence of a semi-colon at the end of the line of code. In Swift, semi-colons are optional and generally only used as a separator when multiple statements occupy the same line of code.

Note that although some extra code has been entered, nothing yet appears in the results panel. This is because the code has...