Declaring classes that adopt protocols

Now, we will declare a class that specifies that it conforms to the ComicCharacter protocol in its declaration in the Playground. Instead of specifying a superclass, the class declaration includes the name of the previously declared ComicCharacter protocol after the class name (AngryDog) and the colon (:). We can read the class declaration as "the AngryDog class conforms to the ComicCharacter protocol."

However, the class doesn't implement any of the required properties and methods specified in the protocol, so it doesn't really conform to the ComicCharacter protocol, as shown in the following code. The code file for the sample is included in the swift_3_oop_chapter_05_02 folder:

    open class AngryDog: ComicCharacter { 
 
    } 

The Playground execution will fail because the AngryDog class doesn't conform to the ComicCharacter protocol, so the Swift compiler generates the following errors and notes. We will see similar error messages...