Solutions to Command Line Arguments homework (https://github.com/CodePlatoon/curriculum/blob/master/phase1/command-line-arguments-homework.md)

calculator.rb

left = ARGV.shift.to_f
while 0 < ARGV.length
  operator = ARGV.shift
  right    = ARGV.shift.to_f
  if '+' == operator
    left += right
  elsif '-' == operator
    left -= right
  elsif '*' == operator
    left *= right
  elsif '/' == operator
    left /= right
  end
end
puts left

join_all.rb

$stdout.puts ARGV.join

print_at.rb

index = ARGV.shift.to_i
$stdout.puts ARGV[index]

print_choose_longest.rb

longest  = ""
comparer = ARGV.shift
ARGV.each do |arg|
  if comparer == 'first'
    longest = arg if longest.length < arg.length
  else
    longest = arg if longest.length <= arg.length
  end
end
$stdout.puts longest unless longest.length == 0

print_each.rb

ARGV.each { |arg| $stdout.puts arg }

print_first_longest.rb

longest = ""
ARGV.each { |arg| longest = arg if longest.length < arg.length }
$stdout.puts longest unless longest.length == 0

print_last_longest.rb

longest = ""
ARGV.each { |arg| longest = arg if longest.length <= arg.length }
$stdout.puts longest unless longest.length == 0