modify

13.object_oriented_programming.md

@@ -36,14 +36,19 @@
 
 最简单的类（Class）可以通过下面的案例来展示（保存为 `oop_simplestclass.py`）：
 
-```text
-{% include "./programs/oop_simplestclass.py" %}
+```python
+class Person:
+    pass  # 一个空的代码块
+
+p = Person()
+print(p)
 ```
 
 输出：
 
 ```text
-{% include "./programs/oop_simplestclass.txt" %}
+$ python oop_simplestclass.py
+<__main__.Person instance at 0x10171f518>
 ```
 
 **它是如何工作的**
@@ -58,14 +63,22 @@
 
 我们已经在前面讨论过类与对象一如函数那般都可以带有方法（Method），唯一的不同在于我们还拥有一个额外的 `self` 变量。现在让我们来看看下面的例子（保存为 `oop_method.py`）。
 
-```text
-{% include "./programs/oop_method.py" %}
+```python
+class Person:
+    def say_hi(self):
+        print('Hello, how are you?')
+
+p = Person()
+p.say_hi()
+# 前面两行同样可以写作
+# Person().say_hi()
 ```
 
 输出：
 
 ```text
-{% include "./programs/oop_method.txt" %}
+$ python oop_method.py
+Hello, how are you?
 ```
 
 **它是如何工作的**
@@ -80,14 +93,25 @@
 
 案例（保存为 `oop_init.py`）：
 
-```text
-{% include "./programs/oop_init.py" %}
+```python
+class Person:
+    def __init__(self, name):
+        self.name = name
+
+    def say_hi(self):
+        print('Hello, my name is', self.name)
+
+p = Person('Swaroop')
+p.say_hi()
+# 前面两行同时也能写作
+# Person('Swaroop').say_hi()
 ```
 
 输出：
 
 ```text
-{% include "./programs/oop_init.txt" %}
+$ python oop_init.py
+Hello, my name is Swaroop
 ```
 
 **它是如何工作的**
@@ -110,14 +134,84 @@ _字段（Field）_有两种类型——类变量与对象变量，它们根据
 
 **对象变量（Object variable）**由类的每一个独立的对象或实例所拥有。在这种情况下，每个对象都拥有属于它自己的字段的副本，也就是说，它们不会被共享，也不会以任何方式与其它不同实例中的相同名称的字段产生关联。下面一个例子可以帮助你理解（保存为 `oop_objvar.py`）：
 
-```text
-{% include "./programs/oop_objvar.py" %}
+```python
+# coding=UTF-8
+
+class Robot:
+    """表示有一个带有名字的机器人。"""
+
+    # 一个类变量，用来计数机器人的数量
+    population = 0
+
+    def __init__(self, name):
+        """初始化数据"""
+        self.name = name
+        print("(Initializing {})".format(self.name))
+
+        # 当有人被创建时，机器人
+        # 将会增加人口数量
+        Robot.population += 1
+
+    def die(self):
+        """我挂了。"""
+        print("{} is being destroyed!".format(self.name))
+
+        Robot.population -= 1
+
+        if Robot.population == 0:
+            print("{} was the last one.".format(self.name))
+        else:
+            print("There are still {:d} robots working.".format(
+                Robot.population))
+
+    def say_hi(self):
+        """来自机器人的诚挚问候
+
+        没问题，你做得到。"""
+        print("Greetings, my masters call me {}.".format(self.name))
+
+    @classmethod
+    def how_many(cls):
+        """打印出当前的人口数量"""
+        print("We have {:d} robots.".format(cls.population))
+
+
+droid1 = Robot("R2-D2")
+droid1.say_hi()
+Robot.how_many()
+
+droid2 = Robot("C-3PO")
+droid2.say_hi()
+Robot.how_many()
+
+print("\nRobots can do some work here.\n")
+
+print("Robots have finished their work. So let's destroy them.")
+droid1.die()
+droid2.die()
+
+Robot.how_many()
 ```
 
 输出：
 
 ```text
-{% include "./programs/oop_objvar.txt" %}
+$ python oop_objvar.py
+(Initializing R2-D2)
+Greetings, my masters call me R2-D2.
+We have 1 robots.
+(Initializing C-3PO)
+Greetings, my masters call me C-3PO.
+We have 2 robots.
+
+Robots can do some work here.
+
+Robots have finished their work. So let's destroy them.
+R2-D2 is being destroyed!
+There are still 1 robots working.
+C-3PO is being destroyed!
+C-3PO was the last one.
+We have 0 robots.
 ```
 
 **它是如何工作的**
@@ -172,14 +266,67 @@ how_many = classmethod(how_many)
 
 我们将通过下面的程序作为案例来进行了解（保存为 `oop_subclass.py`）：
 
-```text
-{% include "./programs/oop_subclass.py" %}
+```python
+# coding=UTF-8
+
+class SchoolMember:
+    '''代表任何学校里的成员。'''
+    def __init__(self, name, age):
+        self.name = name
+        self.age = age
+        print('(Initialized SchoolMember: {})'.format(self.name))
+
+    def tell(self):
+        '''告诉我有关我的细节。'''
+        print('Name:"{}" Age:"{}"'.format(self.name, self.age), end=" ")
+
+
+class Teacher(SchoolMember):
+    '''代表一位老师。'''
+    def __init__(self, name, age, salary):
+        SchoolMember.__init__(self, name, age)
+        self.salary = salary
+        print('(Initialized Teacher: {})'.format(self.name))
+
+    def tell(self):
+        SchoolMember.tell(self)
+        print('Salary: "{:d}"'.format(self.salary))
+
+
+class Student(SchoolMember):
+    '''代表一位学生。'''
+    def __init__(self, name, age, marks):
+        SchoolMember.__init__(self, name, age)
+        self.marks = marks
+        print('(Initialized Student: {})'.format(self.name))
+
+    def tell(self):
+        SchoolMember.tell(self)
+        print('Marks: "{:d}"'.format(self.marks))
+
+t = Teacher('Mrs. Shrividya', 40, 30000)
+s = Student('Swaroop', 25, 75)
+
+# 打印一行空白行
+print()
+
+members = [t, s]
+for member in members:
+    # 对全体师生工作
+    member.tell()
 ```
 
 输出：
 
 ```text
-{% include "./programs/oop_subclass.txt" %}
+$ python oop_subclass.py
+(Initialized SchoolMember: Mrs. Shrividya)
+(Initialized Teacher: Mrs. Shrividya)
+(Initialized SchoolMember: Swaroop)
+(Initialized Student: Swaroop)
+
+Name:"Mrs. Shrividya" Age:"40" Salary: "30000"
+Name:"Swaroop" Age:"25" Marks: "75"
 ```
 
 **它是如何工作的**