类的继承

class Animal:
    """动物基类"""
    
    def __init__(self, name):
        self.name = name
    
    def make_sound(self):
        """发出声音"""
        print(f"{self.name}发出了声音")

# 继承 Animal 类
class Dog(Animal):
    """狗类"""

    sound = "汪汪汪"

    def __init__(self, name):
        # 调用父类构造方法
        Animal.__init__(self, name)

    # 重写父类方法
    def make_sound(self):
        """狗叫"""
        # 调用父类方法
        super().make_sound()
        print(Dog.sound)

dog = Dog("旺财")
dog.make_sound() # 旺财发出了声音 汪汪汪

class Animal:
    """动物基类"""
    
    def __init__(self, name):
        self.name = name
    
    def make_sound(self):
        """发出声音"""
        print(f"{self.name}发出了声音")

class Swimmer:
    """游泳能力混入类"""
    
    def swim(self):
        print("在水中游泳")

class Duck(Animal, Swimmer):
    """鸭类"""

    sound = "嘎嘎嘎"

    def __init__(self, name):
        Animal.__init__(self, name)
        # 不需要调用Swimmer的__init__，因为它没有

    def make_sound(self):
        """鸭叫"""
        super().make_sound()
        print(Duck.sound)

duck = Duck("小鸭子")
duck.make_sound() # 小鸭子发出了声音 嘎嘎嘎
duck.swim() # 在水中游泳

from abc import ABC, abstractmethod

class Shape(ABC):
    """形状抽象基类"""
    
    def __init__(self, name):
        self.name = name
    
    @abstractmethod
    def calculate_area(self):
        """抽象方法 - 子类必须实现"""
        pass
    
    def display_info(self):
        """具体方法 - 子类可以直接使用"""
        area = self.calculate_area()
        print(f"{self.name}: 面积={area:.2f}")

class Rectangle(Shape):
    def __init__(self, width, height):
        super().__init__("矩形")
        self.width = width
        self.height = height
    
    def calculate_area(self):
        return self.width * self.height

# 使用抽象基类
rectangle = Rectangle(5, 3)

rectangle.display_info()  # 矩形: 面积=15.00, 周长=16.00

# 尝试直接实例化抽象基类会报错
# shape = Shape("测试")  # TypeError: Can't instantiate abstract class Shape