Reply to: http://twitter.com/smahend/status/1136137311

looping.rb

# Here's the example from the book:

input = ''

while input != 'bye'
  puts input
  input = gets.chomp
end

puts 'Come again soon!'

# Let's go through it line by line

# First, set input to an empty string. This is so we
# can check it the first time through the loop. Without
# this, the first time through the loop it would be
# undefined and we'd get an error
input = ''

# This creates the loop, and reads exactly like it does in
# English: "while input is not equal to the string 'bye', do
# some stuff"
while input != 'bye'
  # This is the part inside the loop, which will get
  # run over and over, as long as input isn't set to 'bye'
  puts input
  input = gets.chomp
end

# When/if input gets set to 'bye', then after the loop
# finishes that time through, it will leave the loop and
# end up here
puts 'Come again soon!'


# So, to write your own loop, you need 3 things:
# * initial state/variables
# * a condition to check
# * some code to run inside the loop

some_state = false
while !some_state
  do_something
  do_something_else

  # be sure to change some_state when you're done,
  # or else you'll loop forever and ever and ever and
  # ever and ever and ever and ever....which is fine,
  # if that's what you want.
  if we_are_done
    some_state = true
  end
end