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vector::at vs. vector::operator[]
I know that at() is slower than [] because of its boundary checking, which is also discussed in similar questions like C++ Vector at/[] operator speed or ::std::vector::at() vs operator[] << surprising results!! 5 to 10 times slower/faster! . I just don't understand what the at() met...
Using a strategy pattern and a command pattern
Both design patterns encapsulate an algorithm and decouple implementation details from their calling classes. The only difference I can discern is that the Strategy pattern takes in parameters for execution, while the Command pattern doesn't.
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What are the differences between struct and class in C++?
...ween class and struct is defined in (11.2):
Member of a class defined with the
keyword class are private by
default. Members of a class defined
with the keywords struct or union
are public by default.
Additional difference: the keyword class can be used to declare template parameters, ...
What is the preferred syntax for defining enums in JavaScript?
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Since 1.8.5 it's possible to seal and freeze the object, so define the above as:
const DaysEnum = Object.freeze({"monday":1, "tuesday":2, "wednesday":3, ...})
or
const DaysEnum = {"monday":1, "tuesday":2, "wednesday":3, ...}
Object.free...
Is object empty? [duplicate]
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I'm assuming that by empty you mean "has no properties of its own".
// Speed up calls to hasOwnProperty
var hasOwnProperty = Object.prototype.hasOwnProperty;
function isEmpty(obj) {
// null and undefined are "empty"
if (obj == null) return true;
// Assume if it has a...
Why not use tables for layout in HTML? [closed]
It seems to be the general opinion that tables should not be used for layout in HTML.
66 Answers
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Are static methods inherited in Java?
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All methods that are accessible are inherited by subclasses.
From the Sun Java Tutorials:
A subclass inherits all of the public and protected members of its parent, no matter what package the subclass is in. If the subclass is in the same package as its parent...
Why does NULL = NULL evaluate to false in SQL server
In SQL server if you have nullParam=NULL in a where clause, it always evaluates to false. This is counterintuitive and has caused me many errors. I do understand the IS NULL and IS NOT NULL keywords are the correct way to do it. But why does SQL server behave this way?
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Download File Using Javascript/jQuery
...').src = url;
};
</script>
To force the browser to download a file it would otherwise be capable of rendering (such as HTML or text files), you need the server to set the file's MIME Type to a nonsensical value, such as application/x-please-download-me or alternatively application/octet-stre...
How can I troubleshoot my Perl CGI script?
...is answer is intended as a general framework for working through
problems with Perl CGI scripts and originally appeared on Perlmonks as Troubleshooting Perl CGI Scripts. It is not a complete guide to every
problem that you may encounter, nor a tutorial on bug squashing. It
is just the culmination ...