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Why should I declare a virtual destructor for an abstract class in C++?
...
{
public:
virtual void DoFoo() = 0;
};
class Bar : public IFoo
{
char* dooby = NULL;
public:
virtual void DoFoo() { dooby = new char[10]; }
void ~Bar() { delete [] dooby; }
};
IFoo* baz = new Bar();
baz->DoFoo();
delete baz; // memory leak - dooby isn't deleted
...
Keeping it simple and how to do multiple CTE in a query
...s in one query, as well as reuse a CTE:
WITH cte1 AS
(
SELECT 1 AS id
),
cte2 AS
(
SELECT 2 AS id
)
SELECT *
FROM cte1
UNION ALL
SELECT *
FROM cte2
UNION ALL
SELECT *
FROM cte1
Note, however, that SQL Server may reevaluate t...
Split a List into smaller lists of N size
...
@HaraldCoppoolse the OP didn't ask for selecting, only to split lists
– Phate01
Mar 22 '18 at 16:11
1
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How can I check whether a radio button is selected with JavaScript?
...when one of the fields is null. How can I check whether a radio button is selected?
28 Answers
...
How to add display:inline-block in a jQuery show() function?
...one'); // you could still use `.hide()` here
$('.tabs a').removeClass("selected");
var id = obj.attr("rel");
$('#' + id).css('display', 'inline-block');
obj.addClass("selected");
}
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...
Input widths on Bootstrap 3
Update again: I am closing this question by selecting the top answer to keep people from adding answers without really understanding the question. In reality there is no way to do it with the build in functionality without using grid or adding extra css. Grids do not work well if you are dealing wi...
Multiple “order by” in LINQ
...ow in _db.Movies
orderby row.Category, row.Name
select row;
[EDIT to address comment] To control the sort order, use the keywords ascending (which is the default and therefore not particularly useful) or descending, like so:
var movies = from row in _db.Movies
...
How to avoid the “divide by zero” error in SQL?
...rder to avoid a "Division by zero" error we have programmed it like this:
Select Case when divisor=0 then null
Else dividend / divisor
End ,,,
But here is a much nicer way of doing it:
Select dividend / NULLIF(divisor, 0) ...
Now the only problem is to remember the NullIf bit, if I use the "/"...
Join between tables in two different databases?
...
Yes, assuming the account has appropriate permissions you can use:
SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;
You just need to prefix the table reference with the name of the database it resides in.
...
SQLAlchemy ORDER BY DESCENDING?
...
from sqlalchemy import desc
someselect.order_by(desc(table1.mycol))
Usage from @jpmc26
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