Ruby/Method/Method Arguments

def zeno(start, stop)
  distance = stop - start
  travelled = start
  while travelled < stop and distance > 0
    yield travelled
    distance = distance / 2.0
    travelled += distance
  end
end
steps = 0
zeno(0, 1) { steps += 1 }
steps                                                  # => 54

def endless_string_succession(start)
  while true
    yield start
    start = start.succ
  end
end
endless_string_succession("fol") do |x|
  puts x
  break if x[-1] == x[-2]
end
# fol
# fom
# fon
# foo

def repeat( word="Hello! ", times=3 )
 puts word * times
end
repeat # => Hello! Hello! Hello!
repeat( "Goodbye! ", 5 ) # => Goodbye! Goodbye! Goodbye! Goodbye! Goodbye!

#!/usr/bin/env ruby
def repeat( word, times )
  puts word * times
end
repeat( "Hello! ", 3) # => Hello! Hello! Hello!
repeat "Good-bye! ", 4 # => Good-bye! Good-bye! Good-bye! Good-bye!

def putter(first_word, second_word, third_word)
  puts first_word + " " + second_word + " " + third_word
end
putter "Hello", "from", "Ruby."

array = [1, 2, 3, 4]
def returner(array)
  return array
end
array2 = returner(array)
puts array2

def greeting(message)
  puts message
end
greeting("Hello from Ruby.")

puts "Hello, world!"
puts("Hello, world!")

def inverse(x)
  raise ArgumentError, "Argument is not numeric" unless x.is_a? Numeric
  1.0 / x
end

def inverse(x)
  raise "Argument is not numeric" unless x.is_a? Numeric
  1.0 / x
end
inverse(2)                               # => 0.5
inverse("not a number")
# RuntimeError: Argument is not numeric

def greeting(message)
  puts message
end
 
greeting "Hello from Ruby."

def call_twice
  puts "I"m about to call your block."
  yield
  puts "I"m about to call your block again."
  yield
end
call_twice { puts "Hi, I"m a talking code block." }
# I"m about to call your block.
# Hi, I"m a talking code block.
# I"m about to call your block again.
# Hi, I"m a talking code block.