python如何从其他类访问变量

class ClassA:
    public_var = 10

# 通过类的实例对象访问公有变量
obj = ClassA()
print(obj.public_var)  # 输出: 10

# 通过类名访问公有变量
print(ClassA.public_var)  # 输出: 10

class ClassB:
    __private_var = 20

    def get_private_var(self):
        return self.__private_var

    def set_private_var(self, value):
        self.__private_var = value

obj = ClassB()
print(obj.get_private_var())  # 输出: 20
obj.set_private_var(30)
print(obj.get_private_var())  # 输出: 30

class ClassC:
    _protected_var = 40

    def get_protected_var(self):
        return self._protected_var

    def set_protected_var(self, value):
        self._protected_var = value

obj = ClassC()
print(obj.get_protected_var())  # 输出: 40
obj.set_protected_var(50)
print(obj.get_protected_var())  # 输出: 50