Python - Object-Oriented Programming(classes, Point, Line segment)

Practical Programming
An Introduction to Computer Science
Using Python 3
(Pragmatic Programmers)
(Pragmatic Bookshelf)
Paul Gries (著) Jennifer Campbell (著)
Jason Montojo (著) Lynn Beighley (編集)

開発環境

• OS X Yosemite - Apple (OS)
• Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
• Python 3.4 (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3 (Pragmatic Programmers) (Paul Gries (著)、Jennifer Campbell (著)、Jason Montojo (著)、Lynn Beighley (編集)、Pragmatic Bookshelf)のChapter 14(Object-Oriented Programming)、14.8(Exercises) 5-a, b, c, d.を解いてみる。

14.8(Exercises) 5-a, b, c, d.

コード(BBEdit)

sample5.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import math

# a.
class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
# b.
class LineSegment:
    def __init__(self, start, stop):
        self.start = start
        self.stop = stop
    # c.
    @property
    def slope(self):
        return (self.stop.y - self.start.x) / (self.stop.x - self.start.y)
    # d.
    @property
    def length(self):
        return math.sqrt((self.stop.x - self.start.x) ** 2 +
                         (self.stop.y - self.start.y) ** 2)

if __name__ == '__main__':
    segment = LineSegment(Point(1, 1), Point(3, 2))
    print(segment.slope)
    print(segment.length)

入出力結果(Terminal, IPython)

$ ./sample5.py
0.5
2.23606797749979
$