abstract-class

问题 I have an abstract class. I want to extend the abstract class by another abstract class and then implement the extended abstract class. Is it possible .If yes, whether it's a good approach in point of view regarding OOPS? 回答1: I'm not sure about Java in particular, but it should be valid. In terms of OOP, if it makes sense, then run with it. To use some old examples, you might have a Vehicle abstract class and then LandVehicle and FlyingVehicle abstract classes. As long as your example makes

问题 I have an abstract class. I want to extend the abstract class by another abstract class and then implement the extended abstract class. Is it possible .If yes, whether it's a good approach in point of view regarding OOPS? 回答1: I'm not sure about Java in particular, but it should be valid. In terms of OOP, if it makes sense, then run with it. To use some old examples, you might have a Vehicle abstract class and then LandVehicle and FlyingVehicle abstract classes. As long as your example makes

问题 I have an abstract class. I want to extend the abstract class by another abstract class and then implement the extended abstract class. Is it possible .If yes, whether it's a good approach in point of view regarding OOPS? 回答1: I'm not sure about Java in particular, but it should be valid. In terms of OOP, if it makes sense, then run with it. To use some old examples, you might have a Vehicle abstract class and then LandVehicle and FlyingVehicle abstract classes. As long as your example makes

问题 Given a Java class, something like public abstract class A { public A(URI u) { } } I can extend it in Scala like this class B(u: URI) extends A(u) { } However, what I would like to do is alter the constructor of B, something like case class Settings() class B(settings: Settings) extends A { // Handle settings // Call A's constructor } What's the correct syntax for doing this in Scala? 回答1: Blocks are expressions in Scala, so you can run code before calling the superclass constructor. Here's a

问题 Given a Java class, something like public abstract class A { public A(URI u) { } } I can extend it in Scala like this class B(u: URI) extends A(u) { } However, what I would like to do is alter the constructor of B, something like case class Settings() class B(settings: Settings) extends A { // Handle settings // Call A's constructor } What's the correct syntax for doing this in Scala? 回答1: Blocks are expressions in Scala, so you can run code before calling the superclass constructor. Here's a

问题 Given a Java class, something like public abstract class A { public A(URI u) { } } I can extend it in Scala like this class B(u: URI) extends A(u) { } However, what I would like to do is alter the constructor of B, something like case class Settings() class B(settings: Settings) extends A { // Handle settings // Call A's constructor } What's the correct syntax for doing this in Scala? 回答1: Blocks are expressions in Scala, so you can run code before calling the superclass constructor. Here's a

问题 I have an Interface class which defines the requirements to an active "in-use" class: class Portfolio(ABC): @abstractmethod def update_portfolio(self): raise NotImplementedError @abstractmethod def update_from_fill(self): raise NotImplementedError @abstractmethod def check_signal(self, signal_event): raise NotImplementedError The methods update_portfolio and update_from_fill are both methods which will be the same in 99% of the required cases. Only the check_signal method will vary. Therefore

问题 I have one abstract class -let's say myBase. And I want all the classes derived from myBase to have one static field called public static List<string> MyPArameterNames { get {return _myParameterNames;} } So, every child class can tell what parameter names it uses; I want static because I do not want to create an instance just for this. How can I achieve this? 回答1: You can't do that. Interfaces, abstract, etc. cannot apply to static members. If you want to accomplish this, you will have to

问题 I have one abstract class -let's say myBase. And I want all the classes derived from myBase to have one static field called public static List<string> MyPArameterNames { get {return _myParameterNames;} } So, every child class can tell what parameter names it uses; I want static because I do not want to create an instance just for this. How can I achieve this? 回答1: You can't do that. Interfaces, abstract, etc. cannot apply to static members. If you want to accomplish this, you will have to

问题 I know this question was asked several time, but i don't find how to resolve it. I get this error when i'm trying to build my project: error LNK2019: unresolved external symbol "public: virtual __thiscall IGameState::~IGameState(void)" (??1IGameState@@UAE@XZ) in function "public: virtual __thiscall MenuState::~MenuState(void)" (??1MenuState@@UAE@XZ) Here is my code: IGameState.h class IGameState { public: virtual ~IGameState(); virtual void update() = 0; virtual void render() = 0; };