swap_string.rb

def swap_string(string)
	i = 0
	j = string.length - 1

	while i < j do
		string[i] = (string[i].ord ^ string[j].ord).chr
		string[j] = (string[i].ord ^ string[j].ord).chr
		string[i] = (string[i].ord ^ string[j].ord).chr
		i+=1
		j-=1
	end
	puts string
end


swap_string("HELLO WORLD")
swap_string("THIS IS GREAT")