enums

问题 I have the following statement: private Enum _statusValue; What I'd really like to say is: private Enum _statusValue = 0; even though I know it's redundant. It's just that I like to explicitly specify the initialization. But that is not allowed. Is there some simple way of specifying the initialization on this kind of declaration? EDIT - Let me try again. Here is a contrived / simplified example of what I'm doing. using System; namespace EnumTesting { public enum EFixedPhoneUsability {

问题 This question already has answers here : What is “…” in switch-case in C code (4 answers) Closed 4 years ago . Is '...' symbol is a c language keyword? The code: #include <stdio.h> typedef enum { A=0,B,C,D,E,F,G,H,I,J,K,M } alpha; int main(int argc, char const *argv[]) { alpha table = C; switch (table) { case A ... D: /* I have never seen "..." grammar in textbook */ printf("Oh my god\n"); break; default: printf("default\n"); break; } return 0; } Is ... allowed in C for range? 回答1: It's not

问题 This question already has answers here : What is “…” in switch-case in C code (4 answers) Closed 4 years ago . Is '...' symbol is a c language keyword? The code: #include <stdio.h> typedef enum { A=0,B,C,D,E,F,G,H,I,J,K,M } alpha; int main(int argc, char const *argv[]) { alpha table = C; switch (table) { case A ... D: /* I have never seen "..." grammar in textbook */ printf("Oh my god\n"); break; default: printf("default\n"); break; } return 0; } Is ... allowed in C for range? 回答1: It's not

问题 The problem Suppose I have some code like this: // Events we might receive: enum EventType { PlaySong, SeekTo, StopSong }; // Callbacks we would handle them with: type PlaySongCallback = (name: string) => void; type SeekToCallback = (seconds: number) => void; type StopSongCallback = () => void; In the API I'm given, I can register such a callback with declare function registerCallback(t: EventType, f: (...args: any[]) => void); But I want to get rid of that any[] and make sure I can't

问题 Have a look at the following code: // typescript enum example enum foo { ONE = 1, TWO = 2, THREE = 3 } Is it possible to change the value of ONE to 0 in runtime? If yes, how? 回答1: I don't think the typescript compiler will allow this. But why would you want to change an enum ? The whole point is to have named constant values. If you want them to change, why not just use something like this: const foo = { ONE: 1, TWO: 2, THREE: 3 } 回答2: Is it possible to change the value of ONE to 0 in runtime

问题 I've been using an array of enums with postgres and SQLAlchemy successfully over the past year like so: class MyModel(BaseModel): enum_field = Column(postgresql.ARRAY(EnumField(MyEnum, native_enum=False))) The EnumField is from the sqlalchemy_enum34 library, a small wrapper around the builtin enum that uses Python enums as Python representation instead of strings. Although the docs say, array of enum is not supported, I guess it worked, because I chose 'native_enum=False'. Recently I noticed

问题 I know that an enum enum Year { First, Second, Third, Fourth; } gets converted into final class Year extends Enum<Year> { public static final Year First = new Year(); public static final Year Second = new Year(); public static final Year Third = new Year(); public static final Year Fourth = new Year(); } When I tried to instantiate enum (not class) I got compile time error as: error: enum types may not be instantiated Year y = new Year(); As per my knowledge a private constructor makes a

问题 I have an Enum class RoleType public enum RoleType { SYSTEM_ADMIN, PROJECT_ADMIN, USER; } In my User entity class, I've the following mapping for the enum collection. This is the Java code: @JsonProperty @ElementCollection @Enumerated(EnumType.STRING) @CollectionTable(name = "user_role", joinColumns = @JoinColumn(name = "user_id")) private Set<RoleType> roles; I converted this User entity class to Kotlin and here is the code: @JsonProperty @Enumerated(EnumType.STRING) @ElementCollection

问题 I have an Enum class RoleType public enum RoleType { SYSTEM_ADMIN, PROJECT_ADMIN, USER; } In my User entity class, I've the following mapping for the enum collection. This is the Java code: @JsonProperty @ElementCollection @Enumerated(EnumType.STRING) @CollectionTable(name = "user_role", joinColumns = @JoinColumn(name = "user_id")) private Set<RoleType> roles; I converted this User entity class to Kotlin and here is the code: @JsonProperty @Enumerated(EnumType.STRING) @ElementCollection

问题 I have class like following: class Car { public: Car(); // Some functions and members and <b>enums</b> enum Color { Red, Blue, Black }; Color getColor(); void setColor(Color); private: Color myColor; } I want to: access to Color values as Color::Red . It is really hardly to understand code when Car::Red is used, when class have a lot enums, subclasses etc. use type Color as function argument or return value use variable type Color in switch I know 3 partial solutions: Using embedded class