Structs

A struct groups related fields under one named type — Go has no classes, so a struct plus its associated functions (covered in the next lesson) is how you model a "thing" with data.

main.go

Try it yourself →

package main

import "fmt"

type Person struct {
	Name string
	Age  int
}

func main() {
	alice := Person{Name: "Alice", Age: 30}
	fmt.Println(alice.Name, "is", alice.Age, "years old")
}

Output

Alice is 30 years old

Structs are values

Assigning or passing a struct copies it by default — rect.Width = 12 only changes the local rect variable in main, not some shared instance elsewhere. Printing a struct directly with Println shows all its field values in order.

main.go

Try it yourself →

package main

import "fmt"

type Rectangle struct {
	Width, Height float64
}

func main() {
	rect := Rectangle{Width: 10, Height: 5}
	rect.Width = 12
	fmt.Println(rect)
}

Output

{12 5}

Next: methods — attaching behavior to a struct with receivers.

Practice exercise

Define a struct Book with fields Title string and Pages int. Create a book with Title "Dune" and Pages 412, then print book.Title and book.Pages using fmt.Println(book.Title, book.Pages).

← Maps Methods →