• 2022-06-14
    Animal 是抽象类 ,Dog类和Cat类继承了Animal 。Animal dog = new Dog();的写法是否正确?
  • 内容

    • 0

      在前面几题的基础上,有子类Dog和Cat继承了父类Animal,如下空格的输出是以下哪个选项?dog = Dog(coco,small); cat = Cat(kawaii)>>> isinstance(dog, Animal)___________>>> isinstance(cat, Animal)___________>>> isinstance(dog, Dog)___________>>> isinstance(dog, Cat)____________

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      ‏在前面几题的基础上,有子类Dog和Cat继承了父类Animal,如下空格的输出是以下哪个选项?‍‏dog = Dog('coco','small'); cat = Cat('kawaii') >>> isinstance(dog, Animal) ___________ >>> isinstance(cat, Animal) ___________ >>> isinstance(dog, Dog) ___________ >>> isinstance(dog, Cat) ____________‍ A: True True False False B: True True True False C: True False False True D: True True True True

    • 2

      请定义一个类Dog,使其继承自Animal类,(注:Dog类没有代码)

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      class Animal { public Animal() { System.out.println("Animal!"); } } public class Dog extends Animal{ public Dog() { System.out.println("Dog!"); } public static void main(String[] args) { Dog dog=new Dog(); } }

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      下列各种java类的定义,那种是错误的 A: class Animal{}class Dog extends Animal {} B: final class Animal{}class Dog extends Animal{} C: abstract class Animal{}class Dog extends Animal{} D: public class Animal{}class Dog extends Animal{}