constructor

问题 I followed this link already before asking - Answer is in JAVA context and this for constructor in PHP . Since I am starter, my implementation of my PHP code in OOP concepts, so I am really willing to know about the usage and benefits or when to use constructor in PHP abstract class. Please provide an example in real world context to grab the concept better. PS - Although I am following PHP Manuals to understand OOP concepts but I am finding it little bit hard to understand, any help with the

问题 Bellow is an example I found on Tutorials Points, an example of a constructor. I got most of them, but I just don't get why you need a constructor and a method. public Puppy(String name){ System.out.println("Passed Name is :" + name ); } My question is, what stops you from doing this instead? public static void Puppy(String name){ System.out.println("Passed Name is: "+name); } Doesn't these two do the same thing once called? Here is the full program for reference: public class Puppy { int

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 3 years ago . I wonder if can I say that a constructor is a special case of a method ? 回答1: You can say anything. Whether anyone will disagree with you depends on the context. Some language communities and standards define things that way. More elaborately, it depends on what you mean by a

问题 I was reading this article on Java Generics and there it is mentioned that the constructor for an ArrayList looks somewhat like this: class ArrayList<V> { private V[] backingArray; public ArrayList() { backingArray = (V[]) new Object[DEFAULT_SIZE]; } } I was not able to understand how type erasure and type checking by the compiler happens as explained there. One point I got was that the type parameter is transformed to Object type. I would imagine it as (replacing all V with Object ), but

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: Python (and Python C API): new versus init I'm at college just now and the lecturer was using the terms constructors and initializers interchangeably. I'm pretty sure that this is wrong though. I've tried googling the answer but not found the answer I'm looking for. 回答1: In most OO languages, they are the same step, so he's not wrong for things like java, c++, etc. In python they are done in two steps: __new__

问题 I realize this is a pretty open question and could get a variety of answers, but here goes. Using C# (or Java, or any OO language), is there a general rule that states how many variables should be passed into the constructor? The number of variables I am passing into the constructor of the extended classes seem to be getting out of hand. In an effort to encapsulate the data of a class, I declare the members private, initialize them in my constructor, and use public accessors. Here is an

问题 I'm budiling an application and it lists all the videos i recorded using the recorder in a list. Is it possible for me to create a thumbnail with the help of Uri instead of the string??? my current code goes as below but it no longer works as my input to the constructor is Uri not string. bmThumbnail = ThumbnailUtils.createVideoThumbnail( (db_results.get(position)), Thumbnails.MICRO_KIND); imageThumbnail.setImageBitmap(bmThumbnail); I'm returned the error The method createVideoThumbnail

问题 I have a piece of simple C++ code, in which I defined a template and a global object by specializing the template. The object constructor accesses a static member in the specialized template. But it turns out the static member is not initialized at that point. But for a local object (defined in the body of a function), it works. I'm confused... My c++ compiler is: g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609 ///////////////////////// template<typename T> class TB{ public: const char *

问题 I have the following base class: class NeuralNetworkBase: def __init__(self, numberOfInputs, numberOfHiddenNeurons, numberOfOutputs): self.inputLayer = numpy.zeros(shape = (numberOfInputs)) self.hiddenLayer = numpy.zeros(shape = (numberOfHiddenNeurons)) self.outputLayer = numpy.zeros(shape = (numberOfOutputs)) self.hiddenLayerWeights = numpy.zeros(shape = (numberOfInputs, numberOfHiddenNeurons)) self.outputLayerWeights = numpy.zeros(shape = (numberOfHiddenNeurons, numberOfOutputs)) now, I

问题 Is it a bad programming practice to have try/catch blocks inside constructors? Or does it make no difference as long as our programs handle typeinitializer exceptions gracefully. In C# if there are any exceptions inside a constructor the framework always throws typeinitilizer exceptions. Thanks, Shamika 回答1: System.TypeInitializationException is thrown when a static constructor throws an exception, not on an instance constructor. Exceptions are thrown normally in instance constructors. That