#coding:gbk
class Car():
	'''一次模拟汽车的简单尝试'''
	def __init__(self,make,model,year):
		self.make = make
		self.model = model
		self.year = year
		self.odometer_reading = 0
		
	def get_descriptive_name(self):
		long_name = str(self.year)+' '+self.make+' '+self.model
		return long_name.title()
		
	def read_odometer(self):
		print('this car has '+str(self.odometer_reading)+' miles on it')
		
	def update_odometer(self,mileage):
		if mileage >= self.odometer_reading:
			self.odometer_reading = mileage
		else:
			print('you can`t roll back an odometer!')
	
	def increment_odometer(self,miles):
		self.odometer_reading += miles
	
class ElectricCar(Car):
	'''电动汽车类,继承上一个类'''
	
	def __init__(self,make,model,year):
		'''初始化父类属性'''
		super().__init__(make,model,year)#super是一个特殊的函数
#帮助父类和子类关联起来,这行代码让python调用ElectricCar的父类的
#方法__init__(),让ElectricCar实例包含父类的所有属性
#由于父类也称之为#超类,super因此得名
		self.battery_size = 70
		
	def describe_battery(self):
		print('this car has a '+str(self.battery_size)+'-kwh battery.')
		
my_tesla = ElectricCar('tesla','model s',2016)
print(my_tesla.get_descriptive_name())
my_tesla.describe_battery()