# sing
#
# this silly function is given an integer value and prints the verse of
# "99 Bottles of Beer" that begins with that number
#
def sing(number):
	start = str(number)
	end = str(number-1)

	print "\n" + start + " bottles of beer on the wall, "
	print start + " bottles of beer."
	print "Take one down, and pass it around, "
	print end + " bottles of beer on the wall. "


# getInteger
#
# This function is given a string prompt to use for an input statement
# and solicits a number from the user using that prompt.
#
# If the value entered is an integer, the function returns it. Otherwise
# it requests that the user try again.
#
def getInteger(prompt):
	badNumber = True

	while badNumber:
		badNumber = False	# assume good input
		candidate = raw_input (prompt)
		for i in range (len(candidate)):
			if candidate[i] < "0" or candidate [i] > "9":	# it's not numeric
				badNumber = True
		if badNumber:		# need to ask for another
			print "You entered " + candidate
			candidate = raw_input (prompt)
	return int(candidate)		# return the number to caller


# control
#
# This function asks the user to enter a number to start singing
# the song, and then calls the function repeatedly until
# the number zero is reached (or the user kills the process!)
#
def control():
	print "Let's sing '999 bottles!\n"

	verseNumber = getInteger("Enter the verse you want to start on>> ")

	for verse in range (verseNumber, 0, -1):
		sing(verse)

	print "\n\n Ta-dah!"

control()