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Is SQL or even TSQL Turing Complete?
...e programming languages, so that's kinda cheating).
In this set of slides Andrew Gierth proves that with CTE and Windowing SQL is Turing Complete, by constructing a cyclic tag system, which has been proved to be Turing Complete. The CTE feature is the important part however -- it allows you to crea...
How to do ToString for a possibly null object?
...
It would be great if Convert.ToString() had a proper overload for this.
There's been a Convert.ToString(Object value) since .Net 2.0 (approx. 5 years before this Q was asked), which appears to do exactly what you want:
http://msdn.microsoft.co...
What is the performance cost of having a virtual method in a C++ class?
...any of its parent classes) means that the class will have a virtual table, and every instance will have a virtual pointer.
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How to change the status bar color in Android?
...t of all it's not a duplicate as in How to change the background color of android status bar
19 Answers
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How to write an async method with out parameter?
...el CLR rewrite instead of a
compiler-rewrite. We examined that approach, and it had a lot going
for it, but it would ultimately have been so costly that it'd never
have happened.
A typical workaround for this situation is to have the async method return a Tuple instead.
You could re-write yo...
What should a Multipart HTTP request with multiple files look like? [duplicate]
...ntains binary data, so I'm not posting the request as such - instead, I've converted every non-printable-ascii character into a dot (".").
POST /cgi-bin/qtest HTTP/1.1
Host: aram
User-Agent: Mozilla/5.0 Gecko/2009042316 Firefox/3.0.10
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/...
How to use Comparator in Java to sort
... things with your example class:
it's called People while it has a price and info (more something for objects, not people);
when naming a class as a plural of something, it suggests it is an abstraction of more than one thing.
Anyway, here's a demo of how to use a Comparator<T>:
public c...
App Inventor 2 扩展 · App Inventor 2 中文网
...reate extension components
3.1 Practice creating a sample component
3.2 Convert your sample component to an extension
3.2.2 Test your extension
3.3 Details on creating extensions
3.3.1 When you start to build
3.3.2 Requesting permissions for the extensions you define
3.2.3 Using external li...
Data structure: insert, remove, contains, get random element, all at O(1)
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Consider a data structure composed of a hashtable H and an array A. The hashtable keys are the elements in the data structure, and the values are their positions in the array.
insert(value): append the value to array and let i be its index in A. Set H[value]=i.
remove(value)...
Using Linq to get the last N elements of a collection?
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This approach preserves item order without a dependency on any sorting, and has broad compatibility across several LINQ providers.
It is important to take care not to call Skip with a negative number. Some providers, such as the Entity Framework, will produce an ArgumentException when presented ...