class

Global PHP class in functions?

由 孤街浪徒 提交于 2020-01-23 08:37:07
问题 Is there a way to access one instance of a class inside functions in PHP? Like this: include("class.php"); $bla=new Classname(); function aaa(){ $bla->DoSomething(); //Doesn't work. } $bla->DoSomething(); //Works. 回答1: If I interpret your question correctly, then the proper way to do this is create a singleton class. class Singleton { private static $instance; private function __construct() {} private function __clone() {} public static function getInstance() { if (!Singleton::$instance

Java Static Variables and inheritance and Memory

由 爱⌒轻易说出口 提交于 2020-01-23 06:35:10
问题 I know that if I have multiple instance of the same class all of them are gonna share the same class variables, so the static properties of the class will use a fixed amount of memory no matter how many instance of the class I have. My question is: If I have a couple subclasses inheriting some static field from their superclass, will they share the class variables or not? And if not, what is the best practice/pattern to make sure they share the same class variables? 回答1: If I have a couple

Java Static Variables and inheritance and Memory

由 那年仲夏 提交于 2020-01-23 06:31:45
问题 I know that if I have multiple instance of the same class all of them are gonna share the same class variables, so the static properties of the class will use a fixed amount of memory no matter how many instance of the class I have. My question is: If I have a couple subclasses inheriting some static field from their superclass, will they share the class variables or not? And if not, what is the best practice/pattern to make sure they share the same class variables? 回答1: If I have a couple

Instantiating a class within a class

由 情到浓时终转凉″ 提交于 2020-01-23 04:00:13
问题 I'm trying to instantiate a class within a class, so that the outer class contains the inner class. This is my code: #include <iostream> #include <string> class Inner { private: std::string message; public: Inner(std::string m); void print() const; }; Inner::Inner(std::string m) { message = m; } void Inner::print() const { std::cout << message << std::endl; std::cout << message << std::endl; } class Outer { private: std::string message; Inner in; public: Outer(std::string m); void print()

Java 类，成员变量，成员方法

由 天大地大妈咪最大 提交于 2020-01-23 02:29:45
文章目录 1. 类的定义 2. 成员变量 3. 成员方法 4. 成员变量及成员方法的调用 5. 成员变量和局部变量的区别 1. 类的定义 通过class关键字定义一个类，后面加上类名 public class Student { } 2. 成员变量 定义在类中，方法外的变量称为成员变量 public class Student { // 成员变量 String name ; int age ; } 3. 成员方法 没有static关键字 public class Student { // 成员变量 String name ; int age ; // 成员方法 public void eat ( ) { System . out . println ( "吃饭" ) ; } } 4. 成员变量及成员方法的调用 public class Student { // 成员变量 String name ; int age ; // 成员方法 public void eat ( ) { System . out . println ( "吃饭" ) ; } public static void main ( String [ ] args ) { // 创建一个sc对象 Student sc = new Student ( ) ; // 属性赋值 sc . name = "python" ;

Eclipse Cannot create in-place editor

由 柔情痞子 提交于 2020-01-22 18:20:09
问题 I have a troubleshoot problem. My eclipse don't want open class in the package editor. Error, what i'm having - However, file opened with Open with->Text Editor. That's looks like a charm kinda. help please. 回答1: I encountered this problem in my filename.xhtml using Eclipse Mars . I got it fixed by: 1. Right click on the offending file. 2. Choosing Open With -> Default Editor. After this, everything went back to the way it was. 回答2: Probably your File Association settings are messed up. Open

Eclipse Cannot create in-place editor

由 点点圈 提交于 2020-01-22 18:19:11
问题 I have a troubleshoot problem. My eclipse don't want open class in the package editor. Error, what i'm having - However, file opened with Open with->Text Editor. That's looks like a charm kinda. help please. 回答1: I encountered this problem in my filename.xhtml using Eclipse Mars . I got it fixed by: 1. Right click on the offending file. 2. Choosing Open With -> Default Editor. After this, everything went back to the way it was. 回答2: Probably your File Association settings are messed up. Open

Detect enter in input elements of a certain class

由 一世执手 提交于 2020-01-22 17:39:51
问题 I need to detect when someone hits "enter" in text inputs with a specific class. My jQuery is as follows: $('input.large').keypress(function (e) { if(e.which ==13) console.log("pressed enter"); }); My HTML is something like this: <tr><td> Personal Name </td></tr> <tr><td> <input type='text' class='large'> </td></tr> <tr><td> Email</td></tr> <tr><td> <input type='text' class='large'> </td></tr> When I've given the fields IDs and tried $('#elementid').keypress it worked. But this isn't working.

What prevents me from including a class in Ruby?

由 时间秒杀一切 提交于 2020-01-22 16:24:30
问题 I'm trying to understand some Ruby internals: Attempting to include a class instead of a module , results in a TypeError : (that's by design) class C end class Foo end Foo.include(C) #=> TypeError: wrong argument type Class (expected Module) I would like to know how that type check works "under the hood". Since classes are modules, I assumed Ruby checks whether the argument is an actual instance of Module : C.is_a?(Module) #=> true C.instance_of?(Module) #=> false Sounds reasonable, doesn't

C++ - If an object is declared in a loop, is its destructor called at the end of the loop?

由 [亡魂溺海] 提交于 2020-01-22 13:44:45
问题 In C++, an object's destructor is called at the closing "}" for the block it was created in, right? So this means that if I have: while(some_condition) { SomeClass some_object; some_object.someFunction(); some_variable = some_object.some_member; } Then the destructor for the object created in one iteration of the loop will be called at the end of the loop before another object is created, correct? Thanks. 回答1: Yes. But you could have tested it yourself. This is a language feature that
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