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Lock, mutex, semaphore… what's the difference?
... number of cpu, io or ram intensive tasks running at the same time.
For a more detailed post about the differences between mutex and semaphore read here.
You also have read/write locks that allows either unlimited number of readers or 1 writer at any given time.
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How to count the number of set bits in a 32-bit integer?
...ith a few clever optimizations. Continuing on with the same pattern for 2 more steps can widen to 2x 16-bit then 1x 32-bit counts. But there is a more efficient way on machines with fast hardware multiply:
Once we have few enough "elements", a multiply with a magic constant can sum all the element...
What is the difference between the Facade and Adapter Pattern?
...he shades too. That's a Facade - one button/function that takes care of a more complicated set of steps.
The Adapter pattern just links two incompatible interfaces.
EDIT: A quick analogy for the Adapter pattern (based on the comments) might be something like a DVI-to-VGA adapter. Modern video ca...
Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?
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Simplest way to read json from a URL in java
...n, and I have to concatenate the lines instead of the characters, which is more expensive. That wouldn't keep the code as short as it is now. Furthermore, in JSON notation there is no concept of "lines", so why should I read them as such?
– Roland Illig
Dec 1 '...
What are metaclasses in Python?
... define the type of a class, not just a factory for it, so you can do much more with them. You can, for instance, define normal methods on the metaclass. These metaclass-methods are like classmethods in that they can be called on the class without an instance, but they are also not like classmethods...
How to parse freeform street/postal address out of text, and into components
...or an address verification company. I'm posting the answer here to make it more accessible to programmers who are searching around with the same question. The company I was at processed billions of addresses, and we learned a lot in the process.
First, we need to understand a few things about addres...
How can I dynamically create derived classes from a base class
...le names, known at coding time, or data - and names learned in runtime
are more "data" than "variables" -
So, you could just add your classes to a dictionary and use them from there:
name = "SpecialClass"
classes = {}
classes[name] = ClassFactory(name, params)
instance = classes[name](...)
And ...
Static linking vs dynamic linking
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Dynamic linking can reduce total resource consumption (if more than one process shares the same library (including the version in "the same", of course)). I believe this is the argument that drives it its presence in most environments. Here "resources" includes disk space, RAM, and ...
Why do people say there is modulo bias when using a random number generator?
...e, and so you'll need to perform RAND_MAX/n calls to rand() on average.
A more efficient formula approach would be to take some large range with a length divisible by n, like RAND_MAX - RAND_MAX % n, keep generating random numbers until you get one that lies in the range, and then take the modulus:...