Some math 4 4's thinggy

random_correctness.rb

math_methods = Math.methods(false).each do |m|
  self.class.send(:define_method, m, Proc.new do |x| Math.method(m).(x); end )
end
math_methods.delete_if{|m| %I[atan2 hypot acos asin atan atanh frexp lgamma ldexp].include? m}

def sqrt x
  Math.sqrt x
end
ops       = [' + 4.0 ', ' - 4.0 ', ' * 4.0', ' / 4.0 ',]
mixer = %w[* - + /]
math_methods.each do |math_method|
  ops.concat( mixer.map{|m| "#{m} #{math_method}(4.0) "})
end
solutions = {}

start = Time.now

while true do
  string = '4.0 '
  3.times do
    string += ops.sample
  end
    # puts string
  result =  eval( string)
  if result > 0 and result.to_i.to_f == result and !solutions[result]
    puts string
    puts result
    solutions[result] = string
  end
  break if Time.now - start >= 2*60*60 #two hours timeout because I went for lunch
end

# at_exit do
  puts '======================================='
  solutions.keys.sort.each do |k|
    puts "#{k} = #{solutions[k]}"
  end
  puts '======================================='
# end