swap variables

swap_bench.rb

#!/usr/bin/env ruby

a = 2
b = 4

50000000.times do
  a = a ^ b
  b = a ^ b
  a = a ^ b
end
# 17,97s user 0,01s system 99% cpu 18,005 total

c = nil
50000000.times do
  c = a                                                                                                                  
  a = b
  b = c
end
# 7,16s user 0,01s system 99% cpu 7,180 total