enum class

__slots__ restricting instances to add extra attributesTo achieve the limit, Python allows you to define a special __slots__ variable to limit the attributes that the class instance can add when defining class:class Student (object): __slots_

Java Syntax sugarSyntactic sugars add some syntactic support at the language level to facilitate developer code development, and these syntaxes do not improve the performance of the program, only to improve development efficiency.Java syntax sugar

1. Enumeration class overviewThe enum keyword, used to define an enumeration class, that is the same as the Class,interface keyword. An enumeration class is a special class.But the enumeration class is not a normal class after all, it differs from

First, JSP built-in objectsJSP provides built-in objects based on the Servlet API specification that developers can use to access these objects without declaring them in advance.The JSP provides 9 built-in objects:(a), Request brief:The most

C++11 strongly typed enumerations#define_crt_secure_no_warnings#include#includestring>#include#include//C + + 11 introduces a new enumeration type, "Enum class", also known as "strongly typed enumeration". Declaring type enumeration is very simple,

The code makes the program aesthetically pleasing, and I prefer to read her.Refer to the Google Coding specification http://zh-google-styleguide.readthedocs.io/en/latest/google-cpp-styleguide/File namingGeneral statementFile names are all lowercase

To learn more about annotations, we must be able to define our own annotations and use annotations to define our own annotations before we have to understand the syntax of the meta-annotations and related definition annotations that Java provides us.

Summary of abstract classes:· The biggest difference between abstract classes and ordinary classes is that there are abstract methods in the abstract class, so in the abstract classYou can define attributes, construct methods, and so on· The

Java1.5 provides a keyword enum that makes it easy to define the type of enumeration you need, for example enum Season { SPRING, SUMMER, AUTUMN, WINTER } A seasonal enumeration type is defined.In this case, for season.spring

  Main content: * String related Class (String, StringBuffer) * Basic data Type wrapper class (Byte, Character, short, Integer, Long, Float, Double, Boolean) * Math Class * File class * Enum class     java.lang.string class  * Java.lang.String class

Review the development of Java Annotations (Annotation), reproduced two, are relatively basic, easy to understand. Getting started with a deep understanding of Java: Annotations (Annotation) custom annotations To drill down into annotations, we

1. Variable Parameters Starting with JDK 1.5, Java allows you to define parameters with variable parameter lengths, allowing you to specify an indeterminate number of formal parameters for a method, or add three points after the type of the last

In the program, we often define constants to identify some states, types, and so on. For example, define the status of an order, which can be defined as Order_status_cancel = 1 to indicate that the order status is "Order canceled." But the way the

Java JDK1.5 New features – Enumerations I. Enumeration definition Definition: An enumeration is a special class defined using an enum declaration, but it does not inherit from the Java.lang.Object class, which inherits from the Java.lang.enum class,

Custom annotations: When you use @interface to customize annotations, the Java.lang.annotation.Annotation interface is automatically inherited and other details are automatically completed by the compiler. When you define annotations, you cannot

The Java enum is singleton class (only one instance). Java uses compilers and JVMs to prevent an enum from generating more than one class: You cannot use the new, Clone (), De-serialization, and Reflection APIs to produce an enum's instance. So

/ * About enumeration types 1. The keywords we have now learned about custom data types are Class (Class), Interface (interface), enum (enum) 2. The values () method in the enumeration type is used to enumerate the various types in the enumeration 3.

Iterator Iterator interface1. Iterator interfaceIterableThe built-in method iterator () returns a new iterator.Such as: Public interface Iterable {iterator iterator ();} Iterator has Hasnext () and Next () two methods to implement.

Java collection is a Java-provided toolkit that contains commonly used data structures: collections, lists, queues, stacks, arrays, mappings, and so on. Java Collection Toolkit location is java.util.*Java collections can be divided into 4 main parts:

Nineth Chapter 1, C + + program composition-- (1), header file: Contains the structure declaration and uses these constructs the prototype. (2), source code file: Code that contains a structure-related function. (3), source code file: Contains