V does not have classes. But one can define methods for types. A method is a function that has a special receiver argument, only a receiver of the specified type can execute this function. The receiver has its own argument list between fn and the method name.

struct User {
    name string
    email string
    age int

fn (u User) can_register() bool {
    return u.age > 15

fn (u mut User) has_birthday() {
    u.age += 1

fn main() {
    mut bob := User {
        name: 'Bob'
        email: ''
        age: 15
    alice := User {
        name: 'Alice'
        email: ''
        age: 17
    println(bob.can_register())                                             // false
    println('Bob needs to be 16 to register, but he only is ${bob.age}.')   // Bob needs to be 16 to register, but he only is 15.
    println(alice.can_register())                                           // true
    println(bob.age)                                                        // 16

This code above realizes two methods for receivers u of type User. Note that the method has_birthday() has a mut receiver, this is needed here since we want to change its data. The convention of V is not to use receiver names like self, this or similar things but a short, preferably one letter long, name.


  1. Create a method for the type Person that determines whether a person is underage or not.

  2. Create a method that determines whether an Animal has fur or not.

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