Class method inside class

example.rb

# First
class Example
  def hello
    puts 'hello'
  end
  
  def vinh
    puts 'vinh'
  end
end

example = Example.new # We need initialize Example class,first.
example.hello # call method hello via example's variable --> "hello"

# Second
class Example
  def Example.hello
    puts 'hello'
  end
  
  def Example.vinh
    puts 'vinh'
  end
end

Example.vinh # "vinh"

# By the way, the Second can write
class Example
  def self.hello
    puts 'hello'
  end
  
  def self.vinh
    puts 'vinh'
  end
end

Example.hello # "hello"