Error Handling in Swift

Question 1

What are the two sides to handling errors within Swift? What do they involve?

Answer 1

1. Triggering (or throwing) an error when the desired results are not achieved within the method of an iOS app.
2. Catching and handling the error after it is thrown by a method.

Question 2

The error type value can be of any type that conforms to what?

Answer 2

The ErrorType protocol

Question 3

What is the “throws” keyword used for?

Answer 3

A method or function declares that it can throw an error using the “throws” keyword.

Question 4

What does a “defer” statement do?

Answer 4

Allows a sequence of code statements to be declared as needing to be run as soon as the method returns.

Question 5

Error types are created using values that conform to the ______ protocol and are most commonly implemented as __________.

Answer 5

ErrorType, enumerations

Question 6

Methods and functions that throw errors are declared as such using the ______ keyword.

Answer 6

“throw”

Question 7

The _____ and _____ statements are used within the body of methods and functions using the throw keyword to throw errors based on the ______

Answer 7

guard, throw, error type

Question 8

A throwable method or function is called using the ____ statement which must be encapsulated within a _____ statement.

Answer 8

try, do-catch

Question 9

What does a do-catch statement consist of?

Answer 9

A do-catch statement consists of an exhaustive list of catch pattern constructs, each of which contains the code to be executed in the event of a particular error being thrown.

Question 10

What is a “defer” statements use?

Answer 10

Cleanup tasks can be defined to be executed when a method returns through the use of the “defer” statement.