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What is the advantage of using forwarding references in range-based for loops?
...ol> v(10);
for (auto& e : v)
e = true;
}
This doesn't compile because rvalue vector<bool>::reference returned from the iterator won't bind to a non-const lvalue reference. But this will work:
#include <vector>
int main()
{
std::vector<bool> v(10);
fo...
Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash
... no possibility of hidden or subtle unexpected behavior. However, the most common and idiomatic way is “the mutable way”.
As a final aside, this behavior of Hash default values is noted in Ruby Koans.
† This isn’t strictly true, methods like instance_variable_set bypass this, but they mu...
Right query to get the current number of connections in a PostgreSQL DB
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Note that when the postgres command line tool, PSQL is used for executing this query, the total number of connections is the result of this query - 1 since the psql connection made is also included as a connection
– neonidian
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Grep not as a regular expression
...le $someVar . However, Grep thinks that I am trying to run a regex and is complaining:
6 Answers
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What is the “owning side” in an ORM mapping?
...ing side necessary:
The idea of a owning side of a bidirectional relation comes from the fact that in relational databases there are no bidirectional relations like in the case of objects. In databases we only have unidirectional relations - foreign keys.
What is the reason for the name 'owning s...
How can I select item with class within a DIV?
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MySQL CONCAT returns NULL if any field contain NULL
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How do I Convert DateTime.now to UTC in Ruby?
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How to remove .htaccess password protection from a subdirectory
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How to prevent Browser cache for php site
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