instance

问题 Without long delay, here the code which I have no clue why it does what it does: #include <iostream> class A { private: void print() { std::cout << "A.print() called" << std::endl; }; public: template<typename Foo> class B; //NOTE: no friend! public: A(); B<double>* bd; B<int>* bi; }; template<typename Foo> class A::B{ A* callback; public: B(A* a):callback(a){}; void print() { callback->print(); }; // Why is this working ??? }; A::A():bd(new B<double>(this)),bi(new B<int>(this)){} int main

问题 Sometimes, I come up with situations where a single instance of a class is enough, thanks to collections. An example would be my Decoder class: public class Decoder { private static final Decoder instance = new Decoder(); private final HashMap<Client, State> states = new HashMap<Client, State>(); private Decoder() { } public Packet decode(Client client, ByteBuffer data) { return null; } } But I was thinking, why not just make it so it looks something like: public class Decoder { private

问题 In the ruby pickaxe book, there is a line that says attr_accessor is a class method defined in class Module But isn't attr_accessor an instance method? Am I missing something here? 回答1: Yes, all documentation I can find agrees that attr_accessor is an instance method of Module, and I believe it would have to be an instance rather than class method to do what it does. My guess is that it's just a typo. The authors were probably just trying to point out that rather than being part of the

问题 I have to write a code for class that takes in a temperature value, converts it to kelvin, and then determines if this is greater than, equal to, less than, or whatever to another entered temp. It has to say true or false for each of the boolean possibilities. I can't get it to compare the temperature that is set as t1, with the temperature t that the boolean methods take as a parameter? Any suggestions? Also, quit downvoting me, I know I don't know what I'm doing thats why I asked the

问题 i have learned class is a blueprint of structurally identical items, and the items created using class are called instances. please let me know what are the difference between class, object, instance and attribute in object oriented programming concept. is the object, instance, attribute same? http://en.wikipedia.org/wiki/Class_(computer_programming) 回答1: Typically they are used like so: class - blueprint for creating object instances; defines properties and methods object - synonymous with

问题 hi I have a haskell module which have this data type data Blabla = Blabla [Integer] [Char] [(Integer,Char,Char,Integer,String)] Integer I want to show them like that with using instance show integers=[1,2,3] chars=[a,b,c] specialList=[(1,a,b,2,cd),(3,b,c,4,gh)] interger=44 thanx for helping... 回答1: Assuming you just want the default style, simply adding deriving Show to the end of the line as below should do the job. data Blabla = Blabla [Integer] [Char] [(Integer,Char,Char,Integer,String)]

问题 I have a report that takes one parameter (an order no) and creates a document for that order, pulling in some address fields, etc. My customers want the ability to select multiple order numbers at once and print out say 10 different sheets, one for each order. everything would be the same on each sheet, save for the order specific information. my problem is that currently, toggling the parameter to accept multiple values jams all the information for all 10 orders into the same place on one

问题 I have a class called MainWindow without a default constructor. I have a class called Application , its constructor uses an instance of MainWindow as a parameter. I get an Error C2512, "no appropriate default constructor available" in the definition of the constructor from the class Application. Here's the code of the constructor: Application::Application(HINSTANCE hInstance, MainWindow mainWindow) {...} I'm creating the instance of Application like this: MainWindow window(1000, 1000, false,

问题 I am relatively new to AS and want to know how I can notify that an object I imported has reached it's final frame. Basically I want to create a .fla with a class file maybe and import the .swf as a movieclip in an other fla and maybe have multiple instances of that imported movieclip. Now I would like to know how I can get notified that one instance of the imported movieclip has reached the final frame. Thank you 回答1: You can fire event with dispatchEvent(new Event("eventname")) . Write

问题 I am trying to learn how to group functions by class. As an example, I tried to code a generalized least squares method to find the equation of a best-fitting line between a set of (x,y) coordinates. For my particular case, I chose a simple line y = x + 5 , so slope should be close to 1 and y-intercept should be close to 5 . Running my attempt at a coded solution below produces the error TypeError: set_x() takes 1 positional argument but 2 were given , though I am trying to pass an array of x