reference

问题 I have general question regarding the use of pointers vs. references in this particular scenario. Let's say that I have a function that is going to do some computation and store the value inside an object for later use by the caller. I can implement this by using either pointers or references. Although, I would prefer using references because I trying avoiding pointers as much as possible, are there any pros/cons of one approach over the other. The code using Pointers would be as follows:

问题 $class_name = 'MDB2_Statement_'.$this->phptype; $statement = null; $obj =& new $class_name($this, $statement, $positions, $query, $types, $result_types, $is_manip, $limit, $offset); The above code is old, I would like to change it into something like $class_name='MDB2_Statement_'.$this->phptype; ... $obj_=new class_name($this, $statement, $positions, $query, $types, $result_types, $is_manip, $limit, $offset); $obj=&$obj_; But this doesn't result in correct behaviors. Could anyone offer me a

问题 This question already has answers here : Efficiency of creating new objects in a loop (3 answers) Closed 5 years ago . Is there any difference between for (...) { String temp = "temp"; } and String temp; for (...) { temp = "temp"; } I mean, does Java waste many resources creating/deleting objects in loop? Thank you. 回答1: The difference is in scope of variable. Defined inside loop means visible only inside the loop. Defined outside the loop means visible inside and outside the loop. does Java

问题 I am trying to add a reference to the library stated in the question. But it is throwing an error on the 'windows' section of the library reference. Can anyone help me. Thanks! 回答1: Step 1: Go to "Solution Explorer" Step 2: Right click on "Add reference" Step 3: Search in the ".net" tab for the reference for "System.Windows.dll" Or "System.Windows.Forms.dll" (don't know which one is present there but I would prefer the later) and add it. This should resolve your problem. 来源： https:/

问题 I want to keep total control over my game from the Main MovieClip and nowhere else. But I don't want to pass its instance through constructors neither do any .parent reference thingy from its children. Seems too workaroundish and unstable. A sample situation: public class Main extends MovieClip { public function Main() { addChild(new MainMenu()); } public function startGame():void { trace("Game started"); } } public class MainMenu extends Sprite { public function MainMenu() { var option

问题 I have a question about how C# works. m_MyClass = new MyClass(); Dispatcher.m_MyClass = m_MyClass; If I set m_MyClass = null, will that automatically make Dispatcher.m_MyClass null? 回答1: No . Assigning a different value to a variable of a reference has no effect on other references. Only modifying fields of an instance or using properties or methods which modify those fields will have an effect: m_MyClass = new MyClass(); Dispatcher.m_MyClass = m_MyClass; m_MyClass.MyProp = null; //

问题 Can anyone explain the following behavior? In summary, if you create multiple CLS compliant libraries in Visual Studio 2008 and have them share a common namespace root, a library referencing another library will require references to that library's references even though it doesn't consume them. It's pretty difficult to explain in a single sentence, but here are steps to reproduce the behavior (pay close attention to the namespaces): Create a library called LibraryA and add a a single class

问题 If we make a reference to a vector element and then resize the vector, the reference is no longer valid, the same happens with an iterator: std::vector<int> vec{0, 1, 2, 3, 4, 5}; int& ref = vec[0]; auto itr = vec.begin(); cout << ref << " " << *itr << endl; vec[0] = 7; cout << ref << " " << *itr << endl; vec.resize(100); vec[0] = 3; cout << ref << " " << *itr << endl; Prints out: 0 0 7 7 0 0 // We expected a 3 here And I know that it would be more practical to just keep a reference to the

问题 I've a few Classes from a asembly wich is .Net 2.0. These Classes are makred with Serializable. In my Project, i uses this classes in my Classes, wich are marked with DataContract(IsReference=true) and DataMember. Now I have the Problem, with DataContractSerialiser that it serialises the private fields of my .Net 2.0 Classes, wich will not work. But when I use XMLSerialiser, i cannot use IsReference, and so I can also not do this. Is there a easy (simple) Solutiuon for this? Maybe a someone

问题 I've been having problems exporting my java project to a jar (from Eclipse). There is a file that I've included in the jar named images . It contains all of the image files used by my project. The problem is, my references to those images only work when the project isn't in jar form. I can't figure out why and I'm wondering if I need to change the wording of the image references. This is what I'm doing to reference images: URL treeURL = null; Image tree = null; File pathToTheTree = new File(