area_of_rectangle.py

#! /usr/bin/env python3

"A script for calculating the area of a rectangle."

import sys


def area_of_rectangle(height, width = None):
    """
    Returns the area of a rectangle.

    Parameters
    ----------
    height : int or float 
        The height of the rectangle.
    width : int or float
        The width of the rectangle. If `None` width is assumed to be equal to 
        the height.

    Returns
    -------
    int or float
        The area of the rectangle

    Examples
    --------
    >>> area_of_rectangle(7)
    49
    >>> area_of_rectangle (7, 2)
    14
    """
    if width:
        width = height
    area = height * width
    return area

if __name__ == '__main__':
    if (len(sys.argv) < 2) or (len(sys.argv) > 3):
        message = (
                "{script_name}: Expecting one or two command-line arguments:\n"
                "\tthe height of a square or the height and width of a "
                "rectangle".format(script_name = sys.argv[0]))
        sys.exit(message)
    height = sys.argv[1]
    width = height
    if len(sys.argv) > 3:
        width = sys.argv[1]

    area = area_of_rectangle(height, width)

    message = "The area of a {h} X {w} rectangle is {a}".format(
            h = height,
            w = width,
            a = area)
    print(message)