大约有 40,000 项符合查询结果（耗时：0.0443秒） [XML]
Why is address zero used for the null pointer?
...emory, because it means freeing the pointer again isn't dangerous; when I call malloc it returns a pointer with the value zero if it can't get me memory; I use if (p != 0) all the time to make sure passed pointers are valid, etc.
...
How do I prevent an Android device from going to sleep programmatically?
How do I prevent an Android device from going to sleep programmatically?
8 Answers
8
...
How can I determine whether a 2D Point is within a Polygon?
...integers. Many systems use integers for UI painting (pixels are ints after all), but macOS for example uses float for everything. macOS only knows points and a point can translate to one pixel, but depending on monitor resolution, it might translate to something else. On retina screens half a point ...
What belongs in an educational tool to demonstrate the unwarranted assumptions people make in C/C++?
...ch should help beginners (and intermediate) programmers to recognize and challenge their unwarranted assumptions in C, C++ and their platforms.
...
Get program execution time in the shell
...
To see all versions of time you have installed on your system, you can use type -a time
– spinup
Apr 2 '18 at 14:36
...
When to use PNG or JPG in iPhone development?
...more compressed image formats, and thus be slower to display.
JPG's are smaller to store, but lossy (amount depends on compression level), and to display them requires a much more complicated decoding algorithm. But the typical compression and image quality is usually quite sufficient for photos.
...
What is the difference between concurrency, parallelism and asynchronous methods?
Concurrency is having two tasks run in parallel on separate threads. However, asynchronous methods run in parallel but on the same 1 thread. How is this achieved? Also, what about parallelism?
...
BLE（一）概述&工作流程&常见问题 - 创客硬件开发 - 清泛IT社区，...
...与前面几代不同的是，蓝牙4.0版引入的BLE协议更注重功耗问题，而非通信速率的提升。这也使得低功耗蓝牙更加节能，能使设备的电池维持很长时间，因此在很多可穿戴设备中得到了应用。
0x2 BLE工作流程0x21 工作过程蓝牙适用...
Using Java with Nvidia GPUs (CUDA)
...
First of all, you should be aware of the fact that CUDA will not automagically make computations faster. On the one hand, because GPU programming is an art, and it can be very, very challenging to get it right. On the other hand, beca...
C# vs C - Big performance difference
...
Since you never use 'root', the compiler may have been removing the call to optimize your method.
You could try to accumulate the square root values into an accumulator, print it out at the end of the method, and see what's going on.
Edit : see Jalf's answer below
...