What are methods in golang

#go #programming #tutorial

Hi, I'm Abdulrahman I'm glad to share this blog, in this blog we will talk about methods in golang.
so first we must know Go does not have classes because it doesn't support Object-oriented programming.

What is Object-oriented

Object-oriented its way to allow programmers to declare a function inside the class definition. Go doesn't allow us to do that, we have to declare a method on a struct via a special syntax

because Golang doesn't support Object-oriented programming but Golang has Methods.

What is Methods in golang

Method is a function with a special receiver argument and this method can access the properties of the receiver. Receiver here can be type struct or non type struct like(int-string-etc...)

let's see the syntax with example

Syntax

func (r ReceiverType) funcName(parameters) (result){/*code*/}

this above example is ho we define a method for any Receiver here is => YourStruct
Let’s see a full example to understand how to define a method on a type and how to invoke such a method

package main

type User struct { //define a struct
    FirstName string
    LastName  string
}

in above example we defined a struct has FirstName-LastName and if we want to get the FullName we can get them like this:

package main

import "fmt"

type User struct { 
    FirstName string
    LastName  string
}

func main() {
    user := User{
        "Abdulrahman",
        "Masoud",
    }
    fmt.Print(user.FirstName+" "+user.LastName)
    // Result => Abdulrahman Masoud
}

but in GoLang you are allowed to define a method whose receiver is your struct like we say before.
This receiver is accessible inside the method as shown in the below example:

package main

import "fmt"

type User struct { //define a struct
    FirstName string
    LastName  string
}

// GetFullName method to get full name
func (u User) GetFullName() string {
    return u.FirstName + " " + u.LastName
}

func main() {
    user := User{
        "Abdulrahman",
        "Masoud",
    }
    fmt.Print(user.GetFullName())
    // Result => Abdulrahman Masoud
}

In above example we defined a struct that has the inputs that I need and second, we defined a GetFullName method and add a receiver for this method (u User) => this is the receiver of method

Let's define non type struct

Syntax

package main

import "fmt"

type Age int

func (a Age) GetAgeAfterTenYears() int {
    return int(a + 10)
}

func main() {
    age := Age(22)
    fmt.Print(age.GetAgeAfterTenYears())
    // Result => 32
}

In above example we defined an Age type it's not a struct type its non type struct like we say before Receiver here can be type struct or non type struct