#!/usr/bin/python2

# This is a Python program to display large factorials and test "fact.py".

from fact import factorial
import sys
import os
import string

def usage():
	print "This program calculates large factorials."
	print "Requires and tests \"fact.py\"."
	print
	print "Usage: %s integer_expressions" % os.path.basename(sys.argv[0])
	print
	print "The integer expressions should be separated by spaces."
	print "A factorial is the product of all positive integers <= a given integer."
	sys.exit(2)

args = sys.argv[1:]
if (args == []):
	usage()
else:
	try:
		num = eval(string.join(args))
		print "factorial(", num, ") =", factorial(num)
	except:
		for arg in args:
			num = eval(arg)
			print "factorial(", num, ") =", factorial(num)
