Once you’ve created an optional, you’ll want to be able to access the value inside. However, if you just try to use the optional, you will get a compile-time error:

var a = 4 var b: Int? = 3 let sum = a + b // ERROR: Value of optional type 'Int?' must be unwrapped to a value of type 'Int'

The easiest way to wrap an optional is using the ! operator. This process is called force unwrapping and will break open the optional and let you use the underlying value:

var a = 4 var b: Int? = 3 let sum = a + b! print(sum) // Prints 7

But be careful! If the underlying value is nil, your program will crash:

var a = 4 var b: Int? = nil let sum = a + b! // Fatal error: Unexpectedly found nil while unwrapping an Optional value print(sum)

Make sure to only use the ! operator if you are absolutely sure that the value isn’t nil. To be safe, you can check using an if statement:

var a = 4 var b: Int? = nil if b != nil { let sum = a + b! print(sum) Prints 7 }



Define a variable flightDistance of type Int with a value of 1000, and a variable connectingFlightDistance of type Int? with a value of 2000.


Write an if statement that checks if connectingFlightDistance is not nil.


In the body of the if statement, define a constant totalFlightDistance assigned to the sum of flightDistance and connectingFlightDistance. Then, print the totalFlightDistance.

Take this course for free

Mini Info Outline Icon
By signing up for Codecademy, you agree to Codecademy's Terms of Service & Privacy Policy.

Or sign up using:

Already have an account?