大约有 7,000 项符合查询结果（耗时：0.0145秒） [XML]
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...
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...
How to convert byte array to string and vice versa?
...ly must use a String to hold binary data then the safest way is to use Base64 encoding.
share
|
improve this answer
|
follow
|
...
Convert a list of data frames into one data frame
... 100 0.11 1.000
1 do.call 100 9.39 85.364
2 plyr_rbind.fill 100 12.08 109.818
3 plyr_ldply 100 15.14 137.636
share
|
impro...
Is the sizeof(some pointer) always equal to four?
...on a 16-bit system (if you can find one), 4 on a 32-bit system, and 8 on a 64-bit system, but there's nothing to be gained in relying on a given size.
share
|
improve this answer
|
...
embedding image in html email
...images at various locations in the email.
<img src="data:image/jpg;base64,{{base64-data-string here}}" />
And to make this post usefully for others to:
If you don't have a base64-data string, create one easily at:
http://www.motobit.com/util/base64-decoder-encoder.asp from a image file.
Em...
“历史遗留”漏洞：浅析新型SSL/TLS漏洞FREAK - 创意 - 清泛网 - 专注C/C++及内核技术
...本且包含漏洞的加密方式，包括美国的出口级密钥——512位的RSA密钥。
FREAK漏洞是由法国国家信息与自动化研究所(Inria)和微软的研究人员共同发现的。为此，他们曾研究了OpenSSL v1.01k及之前的协议版本，以及苹果的安全传输机...
笑话几则 - 轻松一刻 - 清泛网 - 专注C/C++及内核技术
...师父跑不了，有银行跟交警看着呢！”
科比惊呆了
一位中国学生问科比:“请问您成功的秘诀是什么？”科比说:“你知道早晨四点的城市是什么样吗？”学生:“知道，一般那时候我还没睡，怎么了？”科比:“没，没什么。...
C++中判断文件、目录是否存在的几种方法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...t.st_mode & _S_IFDIR))
{
isExist = true;
}
_S_IFDIR 是一个标志位，如果是目录的话，该位就会被系统设置。
在linux底下也有相对应的函数stat();
使用方法基本相同：
struct stat fileStat;
if ((stat(dir.c_str(), &fileStat) == 0) && S_ISDIR(fileStat.st...
C语言面试那些事儿──一道指针与数组问题 - C/C++ - 清泛网 - 专注C/C++及内核技术
...cc 4.4.5的运行结果：
size of a: 20 (bytes) （Why? 因为机器是32位的, size of int 为 4 bytes，a有5个int）
size of ptr: 4 (bytes) （ptr是指针，永远不要忘记，32位字长的机器，指针长度是4）
ptr的地址：bfb5c52c （取决于具体情况，这里只是为了...