Ruby

Encapsulation

class Person
  def initialize(name, age)
    @name = name
    @age = age
  end

  def introduce
    puts "Hi, I'm #{@name} and I'm #{@age} years old."
  end
end

person1 = Person.new("Albert",  23)
person1.introduce

class Person
  def initialize(name, age)
    @name = name
    @age = age
  end

  def introduce
    puts "Hi, I'm #{@name} and I'm #{@age} years old."
  end

  protected

    def update_name(new_name)
      @name = new_name
    end
end

class Adult < Person
  def marry(spouse_name)
    new_full_name = "#{@name.split.first} #{spouse_name.split.first}"
    update_name(new_full_name)
  end
end

alice = Adult.new("Alice Smith",  27)
alice.introduce
alice.marry("Richard Roy")
alice.introduce

class Person
  def initialize(name, age)
    @name = name
    @age = age
    @username = generate_username
  end

  def introduce
    puts "Hi, I'm #{@name} and I'm #{@age} years old. My username is #{@username}"
  end

  protected

    def update_name(new_name)
      @name = new_name
    end

  private

    def generate_username
      name_parts = @name.split
      "#{name_parts.first.downcase}_#{@age}"
    end
end

person1 = Person.new("Albert",  23)
person1.introduce