Structs

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Go has a speciel type struct to define custome type with named fields. Struct act like collection of attributes/properties similar to classes in OOPs languages out there, but not exactly.

Structs

Struct can have named attributes of any type and methods can be defined to operate on that. Lets define a Person struct that will contain first_name, last_name and age

type Person struct{
  first_name, last_name string
  age uint8
}

So that’s it, we just defined a person struct with some attributes. Let’s use it. There are many way to initialize an struct, here are some

var p Person

Note when we initialize it without providing any value, go assign default value (zeros of type assigned) to each attributes, depending on there types, like first_name, last_name will be assigned a blank string "" and age will be assigned 0.

This can also be in initialized using new function that allocates memory and return pointer.

p := new(Person)

But most used way is to initialize while passing values to it, here is how

p := Person{first_name: "John", last_name: "Lego", age: 32}
//or we can leave off attribute names if we know order
p := Person{"John", "Lego", 32}

Attributes of a struct can be accessed by . operator. So to access first_name of p of type Person , one can use

p.first_name // John
p.first_name = "Walker" // This would change first_name of object p

Struct with Pointers

Pointers with structs work in same way as they do generally in Go, but Go allows fields to be accessed without explicit de-referencing. For example

package main
import "fmt"
type Person struct {
  Name string
  Age int
}
func main() {
  p := Person{"gopher", 2}
  pp := &p
  pp.Name = "Golang rocks"  // Same can be done via (*pp).Name
  (*pp).Name = "Golang rocks" // Similar to statement above
  fmt.Println(pp.Name)
  fmt.Println((*pp).Name)
}