NEW: Subscribe to Hacking with Swift+ and accelerate your learning! >>

Infinite loops

It’s common to use while loops to make infinite loops: loops that either have no end or only end when you’re ready. All apps on your iPhone use infinite loops, because they start running, then continually watch for events until you choose to quit them.

To make an infinite loop, just use true as your condition. true is always true, so the loop will repeat forever. Warning: Please make sure you have a check that exits your loop, otherwise it will never end.

As an example, we’re going to use while true to print the music of John Cage’s piece 4’33” – if you didn’t know, it’s famous because it’s 4 minutes and 33 seconds of complete silence.

We can write the “music” for this piece using while true, with a condition that exits the loop when we’ve gone around enough times:

var counter = 0

while true {
    print(" ")
    counter += 1

    if counter == 273 {
        break
    }
}
Hacking with Swift is sponsored by Fernando Olivares

SPONSORED Ever ask for help and your reviewer immediately notices issues you missed? Fernando Olivares is a 10-year veteran from Big Nerd Ranch and Lambda School who can help hone your app building skills, and he's just launched a new book that does just that – use the code "hacking" to save $5!

Buy the book

Sponsor Hacking with Swift and reach the world's largest Swift community!

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.7/5

Link copied to your pasteboard.