クラスの宣言、インスタンス生成のサンプル

user_sample.rb

class User
  attr_accessor :first_name, :last_name, :age

  // コンストラクタ Constructor
  def initialize(last_name, first_name, age)
    self.last_name = last_name
    self.first_name = first_name
    self.age = age
  end

  def first_name
    @first_name
  end
  def first_name=(string)
    @first_mame = string
  end

  def name
    last_name + ' ' + first_name
  end
end

user1 = User.new('hoge', 'fuga', 39)
user2 = User.new('Tachibana', 'Yutaka', 30)
user3 = User.new('Nakatsukasa', 'Yuya', 28)
user4 = User.new('Suzuki', 'Takayuki', 28)
user5 = User.new('Teraji', 'Takashi', 32)

users = [user1, user2, user3, user4]

users.each do |user|
  puts user.name
end

sum_age = 0
users.each do |user|
  sum_age += user.age
end
puts sum_age / 5.0