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Guaranteed lifetime of temporary in C++?
... a "full-expression" in this case: printf("%s", strdup(std::string("$$$").c_str()) ); ?I mean if strdup(std::string("$$$").c_str()) is taken as the full expression, then the pointer that strdup sees is valid. If std::string("$$$").c_str() is a full expression, then the pointer that strdup sees is in...
How to add spacing between UITableViewCell
...l the border will be smaller. How can I fix it?
– Bad_Developer
Mar 24 '17 at 11:09
1
Hey, Husam....
apt-get for Cygwin?
...s setup.exe from Windows command line. Example:
cd C:\cygwin64
setup-x86_64 -q -P wget,tar,qawk,bzip2,subversion,vim
For a more convenient installer, you may want to use the
apt-cyg package manager. Its syntax
similar to apt-get, which is a plus. For this, follow the above steps and then
use Cygw...
Group by multiple columns in dplyr, using string vector input
...
Since this question was posted, dplyr added scoped versions of group_by (documentation here). This lets you use the same functions you would use with select, like so:
data = data.frame(
asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE),
a30mvxigxkghc5cdsvxvyv0ja = s...
When should you use constexpr capability in C++11?
...lues over and over?
int func (int n) {
static std::map<int, int> _cached;
if (_cached.find (n) == _cached.end ())
_cached[n] = n > 0 ? n + func (n-1) : n;
return _cached[n];
}
The result
By introducing your silly optimization, you just broke every usage of your function th...
Python Flask, how to set content type
...
Try like this:
from flask import Response
@app.route('/ajax_ddl')
def ajax_ddl():
xml = 'foo'
return Response(xml, mimetype='text/xml')
The actual Content-Type is based on the mimetype parameter and the charset (defaults to UTF-8).
Response (and request) objects are docume...
How to check if an email address exists without sending an email?
...
C:\>telnet STACKOVERFLOW.COM.S9A1.PSMTP.com 25
220 Postini ESMTP 213 y6_35_0c4 ready. CA Business and Professions Code Section 17538.45 forbids use of this system for unsolicited electronic mail advertisements.
helo hi
250 Postini says hello back
mail from: <me@myhost.com>
250 Ok
rcpt ...
Drop all tables whose names begin with a certain string
...RE @cmd varchar(4000)
DECLARE cmds CURSOR FOR
SELECT 'drop table [' + Table_Name + ']'
FROM INFORMATION_SCHEMA.TABLES
WHERE Table_Name LIKE 'prefix%'
OPEN cmds
WHILE 1 = 1
BEGIN
FETCH cmds INTO @cmd
IF @@fetch_status != 0 BREAK
EXEC(@cmd)
END
CLOSE cmds;
DEALLOCATE cmds
This is cleane...
Email validation using jQuery
...javascript for that:
function isEmail(email) {
var regex = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;
return regex.test(email);
}
share
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improve this answer
|
...
Generate random numbers using C++11 random library
...lude <random>
#include <iostream>
int main() {
std::random_device rd;
std::mt19937 mt(rd());
std::uniform_real_distribution<double> dist(1.0, 10.0);
for (int i=0; i<16; ++i)
std::cout << dist(mt) << "\n";
}
We use random_device once to see...