大约有 37,000 项符合查询结果（耗时：0.0607秒） [XML]
Best explanation for languages without null
...f why null is undesirable is that meaningless states should not be representable.
Suppose I'm modeling a door. It can be in one of three states: open, shut but unlocked, and shut and locked. Now I could model it along the lines of
class Door
private bool isShut
private bool isLocked
an...
How does Windows 8 Runtime (WinRT / Windows Store apps / Windows 10 Universal App) compare to Silver
...vent) rather than the old COM model of event sources and sinks. Of other notable things, WinRT also has parametrized ("generic") interfaces.
One other big change is that all WinRT components have metadata available for them, just like .NET assemblies. In COM you kinda sorta had that with typelibs, ...
In C++, is it still bad practice to return a vector from a function?
... as vectors/arrays—in many programming languages. Is this style now acceptable in C++0x if the class has a move constructor, or do C++ programmers consider it weird/ugly/abomination?
...
Benchmarking (python vs. c++ using BLAS) and (numpy)
... new machines I also ran the benchmark for matrix sizes 5000 and 8000.
The table below includes the benchmark results from the original answer (renamed: MKL --> Nehalem MKL, Netlib Blas --> Nehalem Netlib BLAS, etc)
Single threaded performance:
Multi threaded performance (8 threads):
T...
Why is an int in OCaml only 31 bits?
...you take up almost 20 Byte.
However, the trick is that with so-called immutable value types like integers, you usually don't need all the metadata in the object header: you can just leave all that stuff out, and simply synthesize it (which is VM-nerd-speak for "fake it"), when anyone cares to look....
What is the explanation for these bizarre JavaScript behaviours mentioned in the 'Wat' talk for Code
...vaScript does help to make the confusing outputs clearer. See the coercion table below
+-----------------+-------------------+---------------+
| Primitive Value | String value | Numeric value |
+-----------------+-------------------+---------------+
| null | “null” | ...
Efficiency of purely functional programming
...out simulating random access memory using only pointers). Pippenger also establishes that there are algorithms for which that is the best you can do; there are problems which are O(n) in the impure system which are Ω(n log n) in the pure system.
There are a few caveats to be made about this paper....
Pointer expressions: *ptr++, *++ptr and ++*ptr
...fix increment expression
1. Precedence. A quick glance at the precedence table for operators will tell you that postfix increment has a higher precedence (16) than dereference / indirection (15). This means that the complex expression *p++ is going to be grouped as: *(p++). That is to say, the * p...
When to use CouchDB over MongoDB and vice versa
...ility of database? Then CouchDB.
Are you hoping multi databases and multi tables/ collections? Then MongoDB
You have a mobile app offline users and want to sync their activity data to a server? Then you need CouchDB.
Do you need large variety of querying engine? Then MongoDB
Do you need large commu...
Does anyone have benchmarks (code & results) comparing performance of Android apps written in Xamari
...lvik used in Android. I have tested it with HTC Flyer and Acer Iconia Tab tablets to benchmark the C# port of Android through Mono against Java Dalvik, with the C# implementation of Android well and truly trouncing the Java-based Dalvik.
...