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Pimpl idiom vs Pure virtual class interface
... important. It's appropriate for it to be a key in a std::map. Example, a "string" class, or a "date" class, or a "complex number" class. To "copy" instances of such a class makes sense.
An Entity type
Identity is important. Always passed by reference, never by "value". Often, doesn't make sense t...
Performance difference for control structures 'for' and 'foreach' in C#
...date. I did a small test, just to see. Here is the code:
static void Main(string[] args)
{
List<int> intList = new List<int>();
for (int i = 0; i < 10000000; i++)
{
intList.Add(i);
}
DateTime timeStarted = DateTime.Now;
for (int i = 0; i < intList...
Getting distance between two points based on latitude/longitude
...nit.MILES)
>> 243.71201856934454 # in miles
# you can also use the string abbreviation for units:
haversine(lyon, paris, unit='mi')
>> 243.71201856934454 # in miles
haversine(lyon, paris, unit=Unit.NAUTICAL_MILES)
>> 211.78037755311516 # in nautical miles
They claim to have ...
How to start an application without waiting in a batch file?
...g should work, it's very likely you're leaving out some quotes (or putting extras in).
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WatiN or Selenium? [closed]
...
{
IE _ie = null;
object _lock = new object();
IE GetInstance(string UrlFragment)
{
lock (_lock)
{
if (_ie == null)
{
var instances = new IECollection(true); //Find all existing IE instances
var match = instanc...
Why do std::shared_ptr work
...ed rather than just a function pointer. But for this case there is no such extra data, it would be sufficient just to store a pointer to an instantiation of a template function, with a template parameter that captures the type through which the pointer must be deleted.
[*] logically in the sense th...
How to detect if a specific file exists in Vimscript?
...t g:hasVundle = 1 endif
filereadable is what is required, but there's an extra handy step of expand, should you be using ~ in your path:
:function! SomeCheck()
: if filereadable(expand("SpecificFile"))
: echo "SpecificFile exists"
: endif
:endfunction
For example
:echo filereadabl...
Running a cron every 30 seconds
...p;
# Execute the payload, some random duration up to the limit.
# Extra blank line if excess payload.
((delay = RANDOM % maxtime + 1))
((maxtime += 1))
echo "$(date) Sleeping for ${delay} seconds (max ${maxtime})."
[[ ${delay} -gt 30 ]] && echo
sleep ${delay}
...
How to make a great R reproducible example
... and your code in the console and get exactly the same as you have.
Give extra information
In most cases, just the R version and the operating system will suffice. When conflicts arise with packages, giving the output of sessionInfo() can really help. When talking about connections to other appli...
Which one will execute faster, if (flag==0) or if (0==flag)?
... some user declaring them: typedef, enum, struct, class. For example, std::string is user defined, even though you certainly not defined it yourself :)
– Matthieu M.
Jan 7 '11 at 14:29
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