从0开始的Python学习014面向对象编程（推荐）

'''the first class
  from liu
  我们使用class语句后跟类名，创建了一个新的类。这后面跟着一个缩进的语句块形成类体。在这个例子中，我们使用了一个空白块，它由pass语句表示。

接下来，我们使用类名后跟一对圆括号来创建一个对象/实例。（我们将在下面的章节中学习更多的如何创建实例的方法）。为了验证，我们简单地打印了这个变量的类型。它告诉我们我们已经在__main__模块中有了一个Person类的实例。

可以注意到存储对象的计算机内存地址也打印了出来。这个地址在你的计算机上会是另外一个值，因为Python可以在任何空位存储对象。
  '''
class Person:
  pass # 空块 

p = Person()
print (p)
print(__doc__)

class Person:
  def sayHi(self):
    print('Hello,how are you?')

p = Person()
p.sayHi()

'''__init__方法
  __init__一个对象被建立的时候，马上运行。这个方法是对你的对象的初始化。
  这个名称的开始和结尾都是双下划线。'''

class Person:
  def __init__(self,name):
    self.name = name

  def sayHi(self):
    print('Hello,my name is ',self.name)

p = Person('happyLiu')
p.sayHi()

class Person:
  def __init__(self,name):
    print('这是初始化块')
    self.name = name

  def sayHi(self):
    print('Hello,my name is ',self.name)

p = Person('happyLiu')
p.sayHi()

class Person:
  population = 0

  def __init__(self,name):
    self.name = name
    print('Initalizing %s' % self.name)

    Person.population += 1

  def __del__(self):
    print('%s says bye.' % self.name)

    Person.population -= 1

    if Person.population == 0:
      print('I am the last one.')
    else:
      print('There are still %d people left.' % Person.population)

  def sayHi(self):
    print('Hi, my name is %s.' % self.name)

  def howMany(self):
    if Person.population == 1:
      print('I am the only person here.')
    else:
      print('We have %d persons here.' % Person.population)

happy = Person('happyLiu')
happy.sayHi()
happy.howMany()

bob = Person('bob james')
bob.sayHi()
bob.howMany()

del bob

happy.sayHi()
happy.howMany()

class SchoolMember:
  '''Represents any school member.'''
  def __init__(self,name,age):
    self.name = name
    self.age = age
    print('(Initialized SchoolMember: %s)'%self.name)

  def tell(self):
    '''Tell my details.'''
    print('Name:%s Age:%d'%(self.name,self.age))

class Teacher(SchoolMember):
  '''Represents a teacher.'''
  def __init__(self,name,age,salary):
    SchoolMember.__init__(self,name,age)
    self.salary = salary
    print('(Initialized Teacher: %s)' % self.name)

  def tell(self):
    SchoolMember.tell(self)
    print('Salary:"%d"' % self.salary)

class Student(SchoolMember):
  '''Represents a student.'''
  def __init__(self, name, age, marks):
    SchoolMember.__init__(self,name,age)
    self.marks = marks
    print('(Initialized Student: %s)' % self.name)
    
  def tell(self):
    SchoolMember.tell(self)
    print('Marks: "%d"'%self.marks)

t = Teacher('Mr,Liu',25,3000)
s = Student('Swaroop', 22, 75)

print()

members = [t,s]
for member in members:
  member.tell()