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Java code To convert byte to Hexadecimal
...
therefore: 1111 = 0xF in hex.
In Java we can do this all in one shot:
Character.forDigit((bytes[0] >> 4) & 0xF, 16);
The forDigit function just maps the number you pass it onto the set of hexadecimal numbers 0-F.
Step 3: Next we need to isolate the lower order bits. Since the bits...
What is the preferred/idiomatic way to insert into a map?
... }
private:
std::vector<double> m_vec;
};
int main(int argc, char* argv[]) {
std::map<int,Widget> map_W;
ptime t1 = boost::posix_time::microsec_clock::local_time();
for(int it = 0; it < 10000;it++) {
map_W.insert(std::pair<int,Widget>(it,Widget...
Script to kill all connections to a database (More than RESTRICTED_USER ROLLBACK)
... Server 2012 and above
USE [master];
DECLARE @kill varchar(8000) = '';
SELECT @kill = @kill + 'kill ' + CONVERT(varchar(5), session_id) + ';'
FROM sys.dm_exec_sessions
WHERE database_id = db_id('MyDB')
EXEC(@kill);
For MS SQL Server 2000, 2005, 2008
USE master;
DECLARE @kill varchar(8000...
CSS Selector “(A or B) and C”?
...rmit groupings. It's essentially the lowest-precedence logical operator in selectors, so you must use .a.c,.b.c.
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What is the meaning of “POSIX”?
...cannot be used
. is cwd, .. parent
portable filenames
use at most max 14 chars and 256 for the full path
can only contain: a-zA-Z0-9._-
See also: what is posix compliance for filesystem?
Command line utility API conventions
Not mandatory, used by POSIX, but almost nowhere else, notably not in ...
How to find duplicates in 2 columns not 1
..._title for each row.
As far as finding the existing duplicates try this:
select stone_id,
upcharge_title,
count(*)
from your_table
group by stone_id,
upcharge_title
having count(*) > 1
...
MySQL COUNT DISTINCT
...
Select
Count(Distinct user_id) As countUsers
, Count(site_id) As countVisits
, site_id As site
From cp_visits
Where ts >= DATE_SUB(NOW(), INTERVAL 1 DAY)
Group By site_id
...
Why would one omit the close tag?
...r mind.
Bonus: a few gotchas (actually currently one) related to these 2 characters:
Even some well-known libraries may contain excess line endings after ?>. An example is Smarty, even the most recent versions of both 2.* and 3.* branch have this. So, as always, watch for third party code. Bo...
How are software license keys generated?
...ype in.
We must be able to blacklist (revoke) a license key in the case of chargebacks or purchases with stolen credit cards.
No “phoning home” to test keys. Although this practice is becoming more and more prevalent, I still do not appreciate it as a user, so will not ask my users to put up wi...
MySQL query String contains
...
Quite simple actually:
mysql_query("
SELECT *
FROM `table`
WHERE `column` LIKE '%{$needle}%'
");
The % is a wildcard for any characters set (none, one or many). Do note that this can get slow on very large datasets so if your database grows you'll need to use ...