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Virtual/pure virtual explained
...es. What virtual does is to give you polymorphism, that is, the ability to select at run-time the most-derived override of a method.
Consider the following code:
#include <iostream>
using namespace std;
class Base {
public:
void NonVirtual() {
cout << "Base NonVirtual call...
Best way to check for nullable bool in a condition expression (if …)
...en you are trying to evaluate a nullable bool in linq.
For example:
array.Select(v => v.nullableBool ?? false)
(from v in array where v.nullableBool ?? false)
Is cleaner in my opinion as opposed to:
array.Select(v => v.nullableBool.HasValue ? v.nullableBool.Value : false)
(from v in array wh...
How to delete projects in IntelliJ 12?
...n a file menu appears, you can right click the unwanted project folder and select Delete.
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if checkbox is checked, do this
...heckbox').click(function(){
var chk = $(this);
$('p').toggleClass('selected', chk.attr('checked'));
})
in this way your code it's cleaner because you don't have to specify all css properties (let's say you want to add a border, a text style or other...) but you just switch a class
...
How to get the text node of an element?
...his.nodeType == Node.TEXT_NODE;
}).text();
This gets the contents of the selected element, and applies a filter function to it. The filter function returns only text nodes (i.e. those nodes with nodeType == Node.TEXT_NODE).
...
Removing all empty elements from a hash / YAML?
...mplementation is not recursive. As a curiosity, they implemented it using #select instead of #delete_if for performance reasons. See here for the benchmark.
In case you want to backport it to your Rails 3 app:
# config/initializers/rails4_backports.rb
class Hash
# as implemented in Rails 4
# ...
MySQL, update multiple tables with one query
...'blah';
To see what this is going to update, you can convert this into a select statement, e.g.:
SELECT t2.t1_id, t2.t3_id, t1.a, t2.b, t2.c AS t2_c, t3.c AS t3_c
FROM t1
INNER JOIN t2 ON t2.t1_id = t1.id
INNER JOIN t3 ON t2.t3_id = t3.id
WHERE t1.a = 'blah';
An example using the same tables as...
Difference between partition key, composite key and clustering key in Cassandra?
...KEY:
insert into stackoverflow_simple (key, data) VALUES ('han', 'solo');
select * from stackoverflow_simple where key='han';
table content
key | data
----+------
han | solo
COMPOSITE/COMPOUND KEY can retrieve "wide rows" (i.e. you can query by just the partition key, even if you have clusteri...
“File not found” when running new LibGDX project
...s using Android Studio or IntelliJ IDEA, you need to follow these steps:
Select Run -> Edit Configurations from the menu
In the "Working Directory:" text box, append "/android/assets" to the path.
Note that if you execute tasks with gradle, this is not an issue. The gradle.build files are con...
Cannot use identity column key generation with ( TABLE_PER_CLASS )
...refer using 'TABLE' id generation strategy as it triggers lots of queries (select, insert, and update) and maintains locks to generate unique values for primary key. So what would be an alternate solution to this If we have a kinda big Inheritance scenario? It will certainly impact the performance a...