Use of classes and objects in ruby id different to other languages . And tell how to declare and define function in ruby and how to call the functions .
Example : In below example i am creating a program of simple arithmetic program .

class Arith
   def addition(a,b)
     puts a+b
   end
  def subtraction(a,b)
    puts a-b
  end
  def multiplication(a,b)
    puts a*b;
  end
   def divide(a,b)
     puts a/b
   end
   def xor(a,b)
     puts a^b;
   end
// self loop means it is the class method 
   def self.help 
     puts "hepl us"
   end
 end
Arith.help // no need to create objects to call class methods
x = Arith.new // need to create objects to call objects methods
x.addition(4,4) // output : 8
x.subtraction(3,2) // output : 1  
x.multiplication(3,2) // output : 6
x.divide(5,5) // output : 1
x.xor(1,1) // output : 0