#! /usr/bin/env python
"""
example1.py
Illustrate the following concepts:
- Script Structure and Format
- Importing and using packages
- Variable declaration and usage
- Function creations and usage
- Basic Error Handling
"""
# Double underscores indicates hidden / system /script info
__author__ = "Hank Preston"
__author_email__ = "hapresto@cisco.com"
__copyright__ = "Copyright (c) 2016 Cisco Systems, Inc."
__license__ = "MIT"
import sys
# Function definition
def doubler(number):
"""
Given a number, double it and return the value
"""
result = number * 2
return result
# Entry point for program
if __name__ == '__main__':
# Retrieve command line input
try:
input = float(sys.argv[1])
except (IndexError, ValueError) as e:
# Indicates no command line parameter was provided
print("You must provide a number as a parameter to this script")
print("Example: ")
print(" python example1.py 12")
sys.exit(1)
# Double the provided number and print output
answer = doubler(input)
print(answer)