O'Reilly logo

Swift Programming: The Big Nerd Ranch Guide by John Gallagher, Matthew Mathias

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Silver Challenge

Earlier in the chapter we told you that accessing an optional’s value when it is nil will result in a runtime error. Make this mistake by force-unwrapping an optional when it is nil. Next, examine the error and understand what the error is telling you.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required