Interface definition in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an interface in Go?

An interface in Go is a type that defines a set of method signatures. Any type that implements these methods satisfies the interface automatically.

beginner

How do you define an interface in Go?

You define an interface using the type keyword followed by the interface name and the interface keyword with method signatures inside curly braces.<br><br>Example:<br>

type Speaker interface {
    Speak() string
}

beginner

True or False: In Go, a type must explicitly declare it implements an interface.

False. In Go, a type implements an interface implicitly by having the required methods. No explicit declaration is needed.

intermediate

What happens if a type does not implement all methods of an interface it is assigned to?

The Go compiler will raise an error because the type does not satisfy the interface. All methods must be implemented to satisfy the interface.

intermediate

Explain how interfaces help in Go programming.

Interfaces allow writing flexible and reusable code by defining behavior without specifying implementation. Different types can implement the same interface, enabling polymorphism.

How do you declare an interface named 'Mover' with a method 'Move()' in Go?

A func Mover() interface { Move() }

B interface Mover { Move() }

C type Mover struct { Move() }

D type Mover interface { Move() }

In Go, interfaces are declared with 'type' keyword followed by the interface name and 'interface' keyword with method signatures inside braces.

If a type has all methods required by an interface, what must you do to implement that interface?

A Nothing, it implements automatically

B Explicitly declare it implements the interface

C Embed the interface in the type

D Use a special keyword 'implements'

Go uses implicit implementation. If a type has all methods, it automatically satisfies the interface.

What error occurs if a type does not implement all interface methods?

A No error, it works fine

B Runtime panic

C Compile-time error

D Linker error

The Go compiler checks interface satisfaction at compile time and raises an error if methods are missing.

Which of these is NOT true about Go interfaces?

A Interfaces specify method implementations

B Interfaces are satisfied implicitly

C Interfaces enable polymorphism

D Interfaces can hold any type that implements their methods

Interfaces specify method signatures, not implementations.

What keyword is used to define an interface in Go?

A interface

B type

C struct

D func

The 'type' keyword is used to define interfaces, combined with the 'interface' keyword inside the definition.

Describe how you define and use an interface in Go with a simple example.

Think about how you declare an interface and how a struct can implement it without extra keywords.

Explain why interfaces are useful in Go programming and how they support flexible code design.

Consider how interfaces let different types behave similarly without sharing code.