unless Keyword

# 2 ways to use unless keyword - opposite of if expression
hungry = false

unless hungry  #check if something is false
  puts "I'm writing Ruby programs!"   #when not hungry (ie. false)
else
  puts "Time to eat!" #when hungry (ie. true)
end # always end the loop

problem = false
print "Good to go!" unless problem  # statement will be printed since problem is false