methods

问题 Given that I was passing the undefined function: void foo(char, short); I learned how to obtain the type tuple of the arguments by calling decltype(m(foo)) with this function: template <typename Ret, typename... Args> tuple<Args...> m(Ret(Args...)); I would now like to pass an undefined method: struct bar { void foo(char, short); }; I had tried rewriting m like: template <typename Ret, typename C, typename... Args> tuple<Args...> m(Ret(C::*)(Args...)); But when I try to call this similarly

问题 I am using Ruby 1.9.2 and the Ruby on Rails v3.2.2 gem. After my previous question on how to “nest” the inclusion of modules when using the Ruby on Rails ActiveSupport::Concern feature, I would like to understand where I should state methods added to a class by including "nested" modules in order to make these instance methods of that class. That is, I have the following: class MyClass < ActiveRecord::Base include MyModuleA end module MyModuleA extend ActiveSupport::Concern included do

问题 As per java, instance method resolution is based on runtime types of the arguments. But while resolving instance variable it uses different approach as shown below. Output of program is .. Child Parent ParentNonStatic Here First output is based on runtime types of the argument but third output is not. can any one explain about this ? public class Child extends Parent { public static String foo = "Child"; public String hoo = "ChildNonStatic"; private Child() { super(1); } @Override String

问题 I have a small app that uses cocos2d to run through four "levels" of a game in which each level is exactly the same thing. After the fourth level is run, I want to display an end game scene. The only way I have been able to handle this is by making four methods, one for each level. Gross. I have run into this situation several times using both cocos2d and only the basic Cocoa framework. So is it possible for me to count how many times a method is called? 回答1: Can you just increment an

问题 I want to dynamically open a method and return a value based on the input field. I am trying to ask what I want with an example here. If I could succeed this example, I would do what I want. Assume I have a class called Greetings which has a method called greet() which takes message as argument. class Greetings def self.greet(message) return "good morning" if message=="gm" return "evening" if message=="ge" return "good afternoon" if message=="ga" end end When I do a Greetings.greet("ge") , I

问题 I am having trouble finding the issue with my problem. Everything checks out right when I test my program except for one thing. In my print statements while I execute the program, they do not update the health correctly like they should. import java.util.Random; import java.util.Scanner; public class Dragon { private static int health; private static int attack; private static boolean isAlive = true; private static int dragonHealth; private static int dragonAttack; private static boolean

问题 I have tried to use different methods suggested in StackOverflow but I cannot make the following work. I have a nested ChildComponent into a ParentComponent. Here the HTML of the parent: <div> ... <div> <span *ngIf="value" class="option-button cursor-pointer" [attr.modelURL]="value" (click)="$event.stopPropagation();getParts(assemblyLibrary)"> <i class="fa fa-cube"></i> </span> <child-component></child-component> Obviously, I have imported the child component into the parent one: import {

问题 Please look at the code below and explain: what am I doing wrong? function doStuff(a, b){ return a + b + 1 ; } var myContext = { c: 1, d: 3 }; // myContext = this (result => 5) doStuff.call(myContext,myContext.c,myContext.d) // ... so why doesn't the below work? (result => NaN) doStuff.call(myContext,this.c,this.d) // To make the above work, i must replace "this" with "myContext" (result => 5)... doStuff.call(myContext,myContext.c,myContext.d) // ...which is no different to... doStuff

问题 i wrote this code as part of a project and this doesnt seem the most efficient. is there a cleaner way to write this method? public static int numberMonth(int parseMonth, Boolean leapYear) { int month = 0; if (parseMonth < 1) { month = 0; if (parseMonth < 2) { month =+ 31; if (parseMonth < 3) { if (leapYear) { month =+ 29; } else if(!(leapYear)) { month=+28; if (parseMonth < 4) { month =+ 30; if (parseMonth < 5) { month =+ 31; if (parseMonth < 6) { month =+ 31; if (parseMonth < 7) { month =+

问题 Eclipse has an option in Java Compiler tab: Store information about method parameters (usable via reflection) If I checked on the option. I am able to get method parameter via Parameter API. It is good. If I turn on the option, Compiler will stored method parameter information in All my compiling classes. This may make the class/jar file bigger. Eclipse turn it off by default. My question is: Is there any way to turn on the option for some class I want? Is there any compiler directive that I