大约有 44,000 项符合查询结果（耗时：0.0218秒） [XML]
Vim: How to insert in visual block mode?
...
Try this
After selecting a block of text, press Shift+i or capital I.
Lowercase i will not work.
Then type the things you want and finally to apply it to all lines, press Esc twice.
If this doesn't work...
Check if you have +visualextra ...
What is the difference between _tmain() and main() in C++?
...point.
It has one of these two signatures:
int main();
int main(int argc, char* argv[]);
Microsoft has added a wmain which replaces the second signature with this:
int wmain(int argc, wchar_t* argv[]);
And then, to make it easier to switch between Unicode (UTF-16) and their multibyte character...
typedef fixed length array
I have to define a 24-bit data type.I am using char[3] to represent the type. Can I typedef char[3] to type24 ? I tried it in a code sample. I put typedef char[3] type24; in my header file. The compiler did not complain about it. But when I defined a function void foo(type24 val) {} in my C...
#define macro for debug printing in C?
...
#include <stdarg.h>
#include <stdio.h>
void dbg_printf(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
vfprintf(stderr, fmt, args);
va_end(args);
}
You can also use this technique in C99, of course, but the __VA_ARGS__ technique is neater because it uses re...
What is the optimal length for an email address in a database?
...
The maximum length of an email address is 254 characters.
Every email address is composed of two parts. The local part that comes before the '@' sign, and the domain part that follows it. In "user@example.com", the local part is "user", and the domain part is "example.c...
libcurl的使用总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...来对curl_global_init做的工作清理。类似于close的函数。
3.char *curl_version( );
描述: 打印当前libcurl库的版本。
4）CURL *curl_easy_init( );
描述:
curl_easy_init用来初始化一个CURL的指针(有些像返回FILE类型的指针一样). 相应的在调用结束时...
Use '=' or LIKE to compare strings in SQL?
...
To see the performance difference, try this:
SELECT count(*)
FROM master..sysobjects as A
JOIN tempdb..sysobjects as B
on A.name = B.name
SELECT count(*)
FROM master..sysobjects as A
JOIN tempdb..sysobjects as B
on A.name LIKE B.name
Comparing strings with '=' is muc...
Generating a UUID in Postgres for Insert statement?
...d to run psql -d dbname -f SHAREDIR/contrib/module.sql and now it works!!! select uuid_generate_v1(); returns 1 now now. Thanks so much!
– anon58192932
Sep 29 '12 at 22:13
5
...
Concatenate multiple result rows of one column into one, group by another column [duplicate]
...Simpler with the aggregate function string_agg() (Postgres 9.0 or later):
SELECT movie, string_agg(actor, ', ') AS actor_list
FROM tbl
GROUP BY 1;
The 1 in GROUP BY 1 is a positional reference and a shortcut for GROUP BY movie in this case.
string_agg() expects data type text as input. Other ...
How can I check if character in a string is a letter? (Python)
... know about islower and isupper , but can you check whether or not that character is a letter?
For Example:
6 Answers
...