Swift Playgrounds app is a great way to get started coding Swift on the go. To use it:
1- Download Swift Playgrounds for iPad from App Store.
2- Open the app.
3- In the My Playgrounds tab, tap + on the top left corner and then select Blank template.
4- Enter your code.
5- Tap Run My Code to run your code.
6- At the front of each line, the result will be stored in a small square. Tap it to reveal the result.
7- To step slowly through code to trace it, tap the button next to Run My Code.