Well done! You've finished your second iOS tutorial.

Finished App

Along the way, you've picked up some new skills:

  • how to visually breakdown designs into views
  • how to identify and use view components in UIKit
  • how to create UI layouts with auto-layout, constraints and stack views
  • how to programmatically get and set class properties

We've also got to review the basics:

  • navigating Xcode files using the Project Navigator
  • using the Assistant Editor to display files side-by-side
  • creating IBOutlet and IBAction connections with Interface Builder

Another app built. You're well on your way to becoming an awesome iOS developer.

Stop and take a moment to appreciate how far you've come!

A Challenge Approaches

You're not done yet. After you finish soaking in the feel-good emotions, it's time to put your skills to the test.

The Challenge

If you're from another country, or just an avid traveller, you'll know that many countries don't have a custom of tipping. In these countries, our tip calculator won't do us much good.

So instead, you're going to build a Currency Exchange Calculator that you can use when you're traveling abroad. To build our Currency Exchange Calculator app, we'll use make of the same skills and concepts we learned during this tutorial.

As always, try completing this challenge as much on your own as possible. If you do get stuck, you can always refer back to this tutorial for help!

App Design

Currency Exchange Design

Above is an example design you can use to build your Currency Exchange Calculator. It's based off a popular currency convertor on the App Store. Feel free to get creative and add your own style into the app design.


Just like your Tip Calculator, your Currency Exchange Calculator app will involve reading user input and converting it to a different value.

Your app should take a input of U.S. dollars and immediately convert it into a currency of your choice. Some popular currencies you can consider using include the following: Euro, Yen, Rupee, Bitcoin.

Notice that there aren't any text fields or segmented controllers in the design above. Each number is a button that should change the input and output of the currency convertor.

If you'd like a better idea of how the app works, go ahead and download the free version of this popular currency convertor on the App Store. You should not need to purchase anything to download this app.

For your exchange calculation, find the currency conversion rate online and hard-code it into your app.

Good luck the challenge! Remember, you can look back on the tutorial or your previous code if you get stuck.


If you have feedback on this tutorial or find any mistakes, please open issues on the GitHub Repository or comment below.

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