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Pimpl idiom vs Pure virtual class interface
...by "value". Often, doesn't make sense to "copy" instances of the class at all. When it does make sense, a polymorphic "Clone" method is usually more appropriate. Examples: A Socket class, a Database class, a "policy" class, anything that would be a "closure" in a functional language.
Both pImpl ...
Easiest way to check for an index or a key in an array?
... associative array)
[ ${array[key]+abc} ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expansion in Bash manual and the little note
if the colon is omitted, the ope...
How to get the path of a running JAR file?
...
One more note: While calling this function from the Jar, the name of the jar is appended at the end for me, therefore had to execute: path.substring(0, path.lastIndexOf("/") + 1);
– will824
Oct 5 '11 at 15:29...
What's invokedynamic and how do I use it?
I keep hearing about all the new cool features that are being added to the JVM and one of those cool features is invokedynamic. I would like to know what it is and how does it make reflective programming in Java easier or better?
...
How do you increase the max number of concurrent connections in Apache?
...ts 200
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25
First of all, whenever an apache is started, it will start 2 child processes which is determined by StartServers parameter. Then each process will start 25 threads determined by ThreadsPerChild parameter so this means 2 process can se...
Should I index a bit field in SQL Server?
...ng a field with low cardinality (a low number of distinct values) is not really worth doing. I admit I don't know enough about how indexes work to understand why that is.
...
What are the most interesting equivalences arising from the Curry-Howard Isomorphism?
...nd C-H to many interesting logics and formulations of logics to obtain a really wide variety of correspondences. Here I've tried to focus on some of the more interesting ones rather than on the obscure, plus a couple of fundamental ones that haven't come up yet.
evaluation | proof norm...
The new keyword “auto”; When should it be used to declare a variable type? [duplicate]
... v.end(); ++it) //v is some [std] container
{
//..
}
Or, more generally,
//good : auto increases readability here
for(auto it = std::begin(v); it != std::end(v); ++it)//v could be array as well
{
//..
}
But when the type is not very well-known and infrequently used , then I think ...
When should you branch?
... Jan 20 '10 at 11:09
Daniel VassalloDaniel Vassallo
301k6666 gold badges475475 silver badges424424 bronze badges
...
Build vs new in Rails 3
...ng a new Client object from the clients collection, and so it can automatically set the firm_id to some_firm.id, whereas the docs are calling Client.new which has no knowledge of any Firm's id at all, so it needs the firm_id passed to it.
The only difference between some_firm.clients.new and some_f...