Seperate Numbers with Commas

Seperate Numbers with Commas

def separate_comma(number)
   if number < 1000
     puts "silly"
   end
   
  snumb = number.to_s
  array = snumb.split('')
  
  cstr = ''
  counter = 0 
  
  
  array.reverse.each do |i|
    cstr += i
    counter += 1
    
    if counter == 3  
      cstr += ','
      counter = 0
    end
  end
    cstr = cstr.reverse
   if cstr[0] == ',' 
     cstr.slice!(0,1)
   end
   puts cstr
end

separate_comma(100000)