Protocol conformance in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a protocol in Swift?

A protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. Classes, structs, or enums can adopt protocols to provide actual implementations.

beginner

How do you declare that a Swift struct conforms to a protocol?

You add the protocol name after the struct name, separated by a colon. For example: struct MyStruct: MyProtocol { }

beginner

What happens if a type does not implement all requirements of a protocol it claims to conform to?

The Swift compiler will give an error because the type does not fully conform to the protocol requirements.

intermediate

Can a class conform to multiple protocols in Swift? How?

Yes, a class can conform to multiple protocols by listing them separated by commas after the class name. For example: <code>class MyClass: ProtocolA, ProtocolB { }</code>

intermediate

What is the benefit of using protocol conformance in Swift?

It allows different types to share common behavior without inheritance, enabling flexible and reusable code. It also helps with abstraction and writing generic code.

How do you declare that a Swift class conforms to a protocol named 'Drivable'?

A class Car inherits Drivable { }

B class Car implements Drivable { }

C class Car extends Drivable { }

D class Car: Drivable { }

In Swift, you use a colon ':' to declare protocol conformance, not 'implements', 'inherits', or 'extends'.

What must a type do to conform to a protocol?

A Implement all the protocol's required methods and properties

B Only declare the protocol name

C Inherit from the protocol

D Override the protocol's methods

A type must implement all required methods and properties defined in the protocol to conform.

Can a struct conform to a protocol in Swift?

A No, only classes can conform

B Only enums can conform

C Yes, structs can conform to protocols

D Protocols cannot be conformed to

In Swift, structs, classes, and enums can all conform to protocols.

What symbol is used to separate multiple protocols in a conformance list?

A ; (semicolon)

B , (comma)

C & (ampersand)

D | (pipe)

Multiple protocols are separated by commas after the type name.

Why use protocols instead of inheritance?

A Protocols allow multiple conformances and more flexible design

B Protocols are slower than inheritance

C Protocols require less code

D Protocols replace functions

Protocols allow types to conform to multiple protocols, enabling flexible and reusable code beyond single inheritance.

Explain how a Swift type conforms to a protocol and what happens if it does not implement all required members.

Think about the syntax and compiler checks.

Describe the benefits of using protocol conformance in Swift programming.

Consider how protocols help organize and share behavior.