Why don't I need to override the init method?

//: Playground - noun: a place where people can play

import UIKit

// The model of a basic weapon.
class Weapon {
    let name: String
    var range: Int
    let damage: Int

    init(name: String, range: Int, damage: Int) {
        self.name = name
        self.range = range
        self.damage = damage
    }
}


// The model of a basic melee weapon
class Melee: Weapon {
    init(name: String, damage: Int) {
        super.init(name: name, range: 1, damage: damage)

    }
}

// The model of area-of-effect / grenade weapons
class Grenade: Weapon {

    var area: Int

    init(name: String, range: Int, damage: Int, area: Int) {

        self.area = area
        super.init(name: name, range: range, damage: damage)
    }
}


// making an instance of a basic weapon
var basicGun = Weapon(name: "AK-47", range: 30, damage: 20)

// making an instance of a basic melee weapon
var basicSword = Melee(name: "Great Sword", damage: 40)

// making an instance of a basic grenade
var basicGrenade = Grenade(name: "Explosive Grenade", range: 5, damage: 25, area: 40)

// Testing the properties

basicGun
basicGun.name
basicGun.range
basicGun.damage

basicSword
basicSword.name
basicSword.range
basicSword.damage

basicGrenade
basicGrenade.name
basicGrenade.damage
basicGrenade.range
basicGrenade.area