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🏛️ Golang Structs Explained

·394 words·2 mins·
Programming Go Go Structs Golang Programming
Table of Contents

Structs in Go
#

A struct is a composite data type that groups together variables under a single name. These variables, known as fields, can be of different types. Structs are a fundamental concept in Go for creating complex data structures.

Defining and Using Structs
#

You can define a struct using the type and struct keywords. Once a struct type is defined, you can create instances (values) of that struct.

package main

import "fmt"

// Define a struct type
type Person struct {
    Name string
    Age  int
}

func main() {
    // Create an instance of the Person struct
    p1 := Person{Name: "Alice", Age: 30}
    fmt.Println(p1)

    // Accessing struct fields
    fmt.Println("Name:", p1.Name)
    fmt.Println("Age:", p1.Age)

    // You can also create a pointer to a struct
    p2 := &Person{Name: "Bob", Age: 25}
    fmt.Println(p2.Name) // Go automatically dereferences the pointer
}

Methods on Structs
#

Go allows you to define methods on struct types. A method is a function with a special receiver argument. The receiver appears in its own argument list between the func keyword and the method name.

package main

import "fmt"

type Rectangle struct {
    Width, Height float64
}

// A method for the Rectangle struct
func (r Rectangle) Area() float64 {
    return r.Width * r.Height
}

func main() {
    rect := Rectangle{Width: 10, Height: 5}
    fmt.Println("Area:", rect.Area())
}

Embedding Structs
#

Go does not provide inheritance in the traditional sense, but it does support composition through struct embedding. You can embed a struct within another struct to “inherit” its fields and methods.

package main

import "fmt"

type Engine struct {
    Horsepower int
}

func (e Engine) Start() {
    fmt.Println("Engine started.")
}

type Car struct {
    Engine // Embed the Engine struct
    Make   string
    Model  string
}

func main() {
    car := Car{
        Engine: Engine{Horsepower: 300},
        Make:   "Toyota",
        Model:  "Camry",
    }

    // The Car struct now has the fields and methods of Engine
    fmt.Println("Horsepower:", car.Horsepower)
    car.Start()
}

This is a powerful feature that allows for flexible and reusable code.

Key Features of Structs
#

  • Composition: Structs are the primary way to build complex data types in Go.
  • Methods: You can define methods on structs to add behavior.
  • Embedding: Structs can be embedded within other structs to promote code reuse.
  • Value vs. Pointer Receivers: Methods can have either a value or a pointer receiver, which affects whether the method can modify the original struct.

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