implementation

问题 I can't understand the implementation of a while loop in android. Whenever I implement a while loop inside the onCreate() bundle, (code shown below) public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); TextView=(TextView)findViewById(R.id.TextView); while (testByte == 0) updateAuto(); } nothing boots up, and the program enters a "hanging" state after a while and I can't understand why. Testbyte is as follows: byte testByte == 0; and updateAuto() is

问题 I'm attempting to link my .cpp implementation file with my header file - I get this error message from my mac terminal - rowlandev:playground rowlandev$ g++ main.cpp -o main Undefined symbols for architecture x86_64: "Person::Person()", referenced from: _main in main-32e73b.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) Here is the code in my cpp file: #include <iostream> #include "playground.h" using namespace

问题 I wonder how to add state to the chain of decorators that will be available to the consumer. Given this simplified model: abstract class AbstractPizza { public abstract print(...); } class Pizza : AbstractPizza { public int Size { get; set; } public print(...); } abstract class AbstractPizzaDecorator { public Pizza:AbstractPizza; public abstract print(); } class HotPizzaDecorator : AbstractPizzaDecorator { public int Hotness { get; set; } public print(...); } class CheesyPizzaDecorator :

问题 When running git checkout , the mergebase of the old HEAD and the new HEAD can be arbitrarily far back. The naïve implementation would be to linearly apply each diff, yet the operation runs instantly. I have a hunch it might be implemented with something kind of skiplisty for intermediate diff caching, but that's just a guess. Does anybody know how it's implemented? Thanks! :) 回答1: You have a good example on how a checkout is (in principle) implemented in the javascript implementation of Git

问题 I understand that a declaration of a delegate is something like this: public delegate int PerformCalculation(int x, int y); However, there must be more going on. The purpose of the delegate is to provide a pointer to a method, and to do that you encapsulate the reference to the method in the delegate. What kind of structure is this reference held in (internally in the delegate)? I also understand that you can encapsulate a reference to multiple methods in a delegate. Does this mean that there

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I've downloaded the code from this site, compiled it and now trying to test it I got a few problems... I generated two files from compilation encrypt and decrypt and instructions from the site are: The encryption program is called as follows: encrypt password cryptofile It encrypts the standard input (padding it

问题 The problem is simpler than knapsack (or a type of it, without values and only positive weights). The problem consists of checking whether a number can be a combination of others. The function should return true or false . For example, 112 and a list with { 17, 100, 101 } should return false , 469 with the same list should return true , 35 should return false , 119 should return true , etc... Edit: subset sum problem would be more accurate for this than knapsack. 回答1: An observation that will

问题 whats the drawback in implementing the presentation layer inside data layer. i guess that would be much dynamic and performance oriented way to go for, for example if i compile to code (i mean full compile where even aspx is compiled) and after that i need to make some design changes, i dont need to update of compiled library i can make the changes directly here. Please correct me if i am wrong. Here's the link where someone posted it as a drawback. 回答1: haven't logged-in for a while or i'd

问题 I'm making a very simple website with ROR. class Product < ActiveRecord::Base belongs_to :category has_many :photos has_many :ordered_photos, :class_name => 'Photo', :order => 'name' has_one :random_photo_1, :class_name => 'Photo', :order => 'RAND()' def random_photo_2 Photo.find(:first, :conditions => { :product_id => self.id }, :order => 'RAND()') end end During implementing many classes of ActiveRecord, I get doubt, I don't understanding what it's the different between random_photo_1

问题 in ActionScript 3.0, there are a few ways to check a class's extension. for example, if i want to know of a custom class extends Sprite i could use the is operator: trace(MyClass is Sprite); or i could use flash.utils.getQualifiedSuperclassName : trace(getQualifiedSuperclassName(MyClass)); i would like to accept a class as an argument and check to see if the passed class implements an certain interface. is there an equally simple or common way to check if my custom class adheres to an