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Covariance and contravariance real world example
I'm having a little trouble understanding how I would use covariance and contravariance in the real world.
9 Answers
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Is there any advantage of using map over unordered_map in case of trivial keys?
A recent talk about unordered_map in C++ made me realize that I should use unordered_map for most cases where I used map before, because of the efficiency of lookup ( amortized O(1) vs. O(log n) ). Most times I use a map, I use either int or std::string as the key type; hence, I've got...
What is a monad?
Having briefly looked at Haskell recently, what would be a brief, succinct, practical explanation as to what a monad essentially is?
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How do I create a nice-looking DMG for Mac OS X using command-line tools?
I need to create a nice installer for a Mac application. I want it to be a disk image (DMG), with a predefined size, layout and background image.
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What is the best way to solve an Objective-C namespace collision?
Objective-C has no namespaces; it's much like C, everything is within one global namespace. Common practice is to prefix classes with initials, e.g. if you are working at IBM, you could prefix them with "IBM"; if you work for Microsoft, you could use "MS"; and so on. Sometimes the initials refer to ...
Understanding Python super() with __init__() methods [duplicate]
I'm trying to understand the use of super() . From the looks of it, both child classes can be created, just fine.
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How do I set a variable to the output of a command in Bash?
I have a pretty simple script that is something like the following:
14 Answers
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What is the ultimate postal code and zip regex?
I'm looking for the ultimate postal code and zip code regex. I'm looking for something that will cover most (hopefully all) of the world.
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Should I use JSLint or JSHint JavaScript validation? [closed]
I am currently validating my JavaScript against JSLint and making progress on, it's assisting me to write better JavaScript - in particular in working with the Jquery library.
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Why is std::map implemented as a red-black tree?
Why is std::map implemented as a red-black tree ?
6 Answers
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