class SecretNumber
  def initialize
    @secret = rand(20)
  end
  def hint
    puts "The number is #{"not " if secret <= 10}greater than 10."
  end
  private 
  def secret
    @secret
  end
end
s = SecretNumber.new
s.secret

NoMethodError: private method `secret' called for 
 #<SecretNumber:0xb7c2e83c @secret=19>

Error! (Exception?) Here's stdout:
NoMethodError: private method `secret' called for #<SecretNumber:0xb7c28a24 @secret=19>
	from (irb):14

s.hint

The number is greater than 10.

The number is greater than 10.

class LessSecretNumber < SecretNumber
  def hint
    lower = secret-rand(10)-1
    upper = secret+rand(10)+1
    "The number is somewhere between #{lower} and #{upper}."
  end
end
ls = LessSecretNumber.new
ls.hint

ls.hint

ls.hint

class MyClass
  def public_method1
  end
  def public_method2
  end
  protected
  def protected_method1
  end
  private
  def private_method1
  end
  def private_method2
  end
end
class LessSecretNumber
  def compare(other)
    if secret == other.secret
    comparison = "equal to" 
    else
      comparison = secret > other.secret ? "greater than" : "less than"
    end
    "This secret number is #{comparison} the secret number you passed in."
  end  
end
a = LessSecretNumber.new
b = LessSecretNumber.new
a.hint

b.hint

a.compare(b)

NoMethodError: private method `secret' called for 
#<LessSecretNumber:0xb7bfe13c @secret=6>

Error! (Exception?) Here's stdout:
NoMethodError: private method `secret' called for #<LessSecretNumber:0xb7bf8374 @secret=6>
	from (irb):43:in `compare'
	from (irb):55

class SecretNumber
  protected :secret
end
a.compare(b)

b.compare(a)

class MethodWithManySecrets
  :private
  # This method will show up in the RDoc, even though it's private.
  def secret_method_1
  end
  # This method will not show up in the RDoc.
  def secret_method_2 # :nodoc:
  end
end
s.send(:secret)