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App Inventor 2 UrsAI2UDP 拓展 - UDP广播通信协议 · App Inventor 2 中文网
...标识符。然后，接收器会过滤掉它感兴趣的设备。
问题是：App Inventor 没有内置 UDP，而且我找不到可用的扩展。所以自己动手吧。
注意：
如果智能手机和远程站位于同一个（本地）网络中，则扩展可以完美运行。如果智能手...
Unexpected results when working with very big integers on interpreted languages
... supports arbitrary precision. It will produce the correct answer on 32 or 64 bit platforms.
This can be seen by raising 2 to a power far greater than the bit width of the platform:
>>> 2**99
633825300114114700748351602688L
You can demonstrate (with Python) that the erroneous values yo...
How to check if running in Cygwin, Mac or Linux?
...
If I run a script under cygwin by executing "\cygwin64\bin\bash -c scriptname", this doesn't necessarily work. In this situation, the cygwin path doesn't get set up and uname -s ends up calling whatever uname is first in your current path, which on my system turns out to be t...
Drawing an SVG file on a HTML5 canvas
...on to comment on the @Matyas answer, but if the svg's image is also in base64, it will be drawed to the output.
Demo:
var svg = document.querySelector('svg');
var img = document.querySelector('img');
var canvas = document.querySelector('canvas');
// get svg data
var xml = new XMLSerializ...
What is the purpose of base 64 encoding and why it used in HTTP Basic Authentication?
I don't get the Base64 encryption.
7 Answers
7
...
Connecting to remote URL which requires authentication using Java
... = username + ":" + password;
String basicAuth = "Basic " + new String(Base64.getEncoder().encode(userpass.getBytes()));
uc.setRequestProperty ("Authorization", basicAuth);
InputStream in = uc.getInputStream();
share
...
如何查看Oracle用户的SQL执行历史记录？ - 数据库(内核) - 清泛网 - 专注C/...
...相关的语句 必须具有DBA 的权限 虽然这条语句很普通 但是需要的时候很管用 能够及时查出一个人执行sql语句情况
-------oracle 查看已经执行过的sql 这些是存在共享池中的 --------->
select * from v$sqlarea t order by t.LAST_ACTIVE_TIME desc
...
How long is the SHA256 hash?
...each character (instead of 8, like for ASCII), so 256 bits would represent 64 hex characters, therefore you need a varchar(64), or even a char(64), as the length is always the same, not varying at all.
And the demo :
$hash = hash('sha256', 'hello, world!');
var_dump($hash);
Will give you :
$ ph...
What does the C++ standard state the size of int, long type to be?
...c C++ types.
I know that it depends on the architecture (16 bits, 32 bits, 64 bits) and the compiler.
24 Answers
...
What is the difference between an int and a long in C++?
...der Windows they are the same, but for example on Alpha systems a long was 64 bits whereas an int was 32 bits. This article covers the rules for the Intel C++ compiler on variable platforms. To summarize:
OS arch size
Windows IA-32 4 bytes
Windows Intel 64...