class-hierarchy

问题 Edit: Big thanks to Paulw11 for helping me solve this issue. I've added the full code here for easy reuse: Class: import UIKit import MessageUI struct Feedback { let recipients: [String] let subject: String let body: String let footer: String } class FeedbackManager: NSObject, MFMailComposeViewControllerDelegate { private var feedback: Feedback private var completion: ((Result<MFMailComposeResult,Error>)->Void)? override init() { fatalError("Use FeedbackManager(feedback:)") } init?(feedback:

问题 Edit: Big thanks to Paulw11 for helping me solve this issue. I've added the full code here for easy reuse: Class: import UIKit import MessageUI struct Feedback { let recipients: [String] let subject: String let body: String let footer: String } class FeedbackManager: NSObject, MFMailComposeViewControllerDelegate { private var feedback: Feedback private var completion: ((Result<MFMailComposeResult,Error>)->Void)? override init() { fatalError("Use FeedbackManager(feedback:)") } init?(feedback:

问题 I've been trying to learn OOP for the last few weeks as much as I can, and I've learned alot, but I'm not certain of this one, what should my class hierarchy look like? Imagine two classes, here's a Level -class: class Level(object): def __init__(self, level, exp): self.level = level self.exp = exp @property def required_exp(self, level=None): return 80 + 40 * (level or self.level) def add_exp(self, exp): self.exp += exp while self.exp >= self.required_exp: self.exp -= self.required_exp self

问题 I've been trying to learn OOP for the last few weeks as much as I can, and I've learned alot, but I'm not certain of this one, what should my class hierarchy look like? Imagine two classes, here's a Level -class: class Level(object): def __init__(self, level, exp): self.level = level self.exp = exp @property def required_exp(self, level=None): return 80 + 40 * (level or self.level) def add_exp(self, exp): self.exp += exp while self.exp >= self.required_exp: self.exp -= self.required_exp self

问题 Since I am trying to learn more about OOP (Java) I'm working my way through some literature where I found this 'task'. Unfortunately I am having kind of a hard time since I am pretty new to OOP and I don't have any sample solution to this. Maybe some of you can give me some input so can work my way through this. Define a class hierarchy for these classes: quadrilateral convex quadrilateral trapezoid parallelogram rhombus rectangle square Create an instance of each class if possible Define

问题 I am "playing" with virtual inheritance in C++, and I want to know how a class object is laid out. I have those three classes: class A { private: int a; public: A() {this->a = 47;} virtual void setInt(int x) {this->a = x;} virtual int getInt() {return this->a;} ~A() {this->a = 0;} }; class B { private: int b; public: B() {b = 48;} virtual void setInt(int x) {this->b = x;} virtual int getInt() {return this->b;} ~B() {b = 0;} }; class C : public A, public B { private: int c; public: C() {c = 49

问题 I was looking for a diagram which shows the built in types of javascript like Function and String but on google I keep finding diagrams with the browser-related stuff like Window . I'm just looking for the pure js object diagram. I know about the ECMA specification but I'm looking for a diagram because I'm a visual type. 回答1: There's not much depth to the JavaScript types to speak of, the diagram would be fairly flat. It's basically (UML at the end): primitive string primitive number

问题 Consider this class hierarchy: Book extends Goods Book implements Taxable As we know, there is a relationship between a subclass and its superclass (is-a). Q: Is there any relationship like "is-a" between Book and Taxable ? GOOD Answers, but you said that "is-a" is also a relationship between Book and Taxable , but "is-a" is a relation between classes , and an interface is not a class! 回答1: Yes. The relationship is exactly the same Book is a Taxable too. EDIT An interface is an artifact that

问题 Often when including namespaces or assemblies into my code, I often run into strange cases where a namespace is inherited from another, yet classes from the parent namespace are not available. For example, when using List<> or Dictionary<> , I use the System.Collections.Generic namespace. However, if I also want to use an IEnumerator , I also have to include the System.Collections namespace. Shouldn't System.Collections already be referenced by any member of System.Collections.Generic , as it

问题 I'm confused in python class hierarchy. I want to know the relation between type and object. object is the top of 'issubclass()' function. type is the top of 'thing. class ' and 'type(thing)'. (I intentionally didn't use the word object again to avoid confusion. instead I used thing.) Surprisingly isinstance(object, type) and isinstance(type, object) both return true. Explain the hierarchy in detail. Thanks I mean which one was written first? type? or object? 回答1: In Python, everything is an