a,b,c=gets.split.map(&:to_i)

STDIN.read.split("\n") #read until EOF rather than iterate
# this may be equivalent
$<.read.split("\n")
$<.read.split.drop(1) #eg: to eliminate size given
$<.to_a
$<.each{|e|p e}

# read full input
gets('')
p $_
p `dd` # read from dd

msg = "Tiam his  message"
msg.chomp.split.to_s            # => ["Tiam", "his", "message"]
msg.chomp.split(/\s/).to_s		# => ["Tiam", "his", "", "message"]

s = "Hello, my\n       name is Michael."
s.split.join(' ') #=> "Hello, my name is Michael."

"input".bytes     { |c| puts c }
"input".each_char { |c| puts c }
"input".chars.map { |c| puts c }	# => "input".split('').map

# not short but usefull
str.each_char.with_index { |c,i| puts c,i }

acc = ''
str.chars.map {|c| acc += c }

puts "%0.1f %s" % [a,b]

puts "%x" % 10 # a
puts "%X" % 10 # A
puts "%#x" % 10 # 0ba , probleme 0 => gives 0 and not 0x0

"0x0a".hex  # => 10

?[          # => "["

116.chr          # => "t"
[116].pack('U*') # => "t"

"t".ord          # => 116
"t".unpack('U*') # => [106]

"string".bytes   # =>  "string".chars.map(&:ord)

"1234".to_i.to_s(2)
"%b" % "1234"

h={}
h[1]^=1 #=> nil^1  -> true
h[1]^=1 #=> true^1 -> false

*(1..10)         # => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
[*1..3, *?a..?c] # => [1, 2, 3, "a", "b", "c"]

[1, nil, 3, nil, nil].compact => [1, 3] 

a = ["test", "test2", "s"]
a.sort_by!{|str| str.length}.reverse!

a.sort_by! { |s| -s.length } # shorter

array.map!(&:to_i)

array.reduce(:+)		# or inject (alias)

[1, 2, 3, 4].sum

"0" * 99

["a", "b", "c", "b"].tally #=> {"a"=>1, "b"=>2, "c"=>1}

fact = -> (x){ x < 2 ? 1 : x*fact.(x-1)}

p fact.call(5)
p fact.(5)
p fact[5]