Does Go support inheritance?

Not in the class-based sense. Go favors composition: you embed one struct in another and use interfaces to share behavior.

How does a type implement an interface in Go?

Implicitly. If a type has all the methods an interface requires, it satisfies the interface; there is no implements keyword.

Go Structs, Methods, and Interfaces

Introduction

Go doesn't have classes. Instead, you group data in structs, attach behavior with methods, and describe what a type can do with interfaces. This tutorial builds a few shapes to show how the three fit together.

Prerequisites

Go installed
Understanding of functions and basic types

Step-by-Step Guide

Step 1: Define a struct and a method

A struct groups related fields. A method is a function with a receiver, written between func and the method name.

type Rectangle struct {
    Width, Height float64
}

func (r Rectangle) Area() float64 {
    return r.Width * r.Height
}

Step 2: Use a pointer receiver to modify a value

A method with a value receiver works on a copy. Use a pointer receiver (*Rectangle) when the method needs to change the original.

func (r *Rectangle) Scale(factor float64) {
    r.Width *= factor
    r.Height *= factor
}

rect := Rectangle{Width: 3, Height: 4}
rect.Scale(2)
fmt.Println(rect.Area())   // 48

Step 3: Describe behavior with an interface

An interface lists method signatures. Any type with those methods satisfies it automatically, without declaring that it does so.

import "math"

type Shape interface {
    Area() float64
}

type Circle struct {
    Radius float64
}

func (c Circle) Area() float64 {
    return math.Pi * c.Radius * c.Radius
}

Step 4: Write code against the interface

A function that accepts a Shape works with any type that has an Area method.

func printArea(s Shape) {
    fmt.Printf("Area: %.2f\n", s.Area())
}

printArea(Rectangle{Width: 3, Height: 4})   // Area: 12.00
printArea(Circle{Radius: 2})                // Area: 12.57

FAQs

Does Go support inheritance?: Not in the class-based sense. Go favors composition: you embed one struct in another and use interfaces to share behavior.
How does a type implement an interface in Go?: Implicitly. If a type has all the methods an interface requires, it satisfies the interface; there is no implements keyword.

Summary

Structs hold data, methods add behavior, and interfaces let functions work with any type that has the right methods. Use pointer receivers when a method must modify its receiver.