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Why are function pointers and data pointers incompatible in C/C++?
...be converted back to the original function pointer type, using an explicit cast, without loss of information. Note: The ISO C standard does not require this, but it is required for POSIX conformance.
– Jonathan Leffler
Sep 11 '12 at 18:23
...
What is an example of the Liskov Substitution Principle?
...
A great example illustrating LSP (given by Uncle Bob in a podcast I heard recently) was how sometimes something that sounds right in natural language doesn't quite work in code.
In mathematics, a Square is a Rectangle. Indeed it is a specialization of a rectangle. The "is a" makes you...
Using the Swift if let with logical AND operator &&
...n("do stuff")
}
This uses the where clause.
Another example, this time casting AnyObject to Int, unwrapping the optional, and checking that the unwrapped optional meets the condition:
if let w = width as? Int where w < 500
{
println("success!")
}
For those now using Swift 3, "where" ha...
Measuring execution time of a function in C++
...::high_resolution_clock::now();
auto duration = std::chrono::duration_cast<std::chrono::microseconds>( t2 - t1 ).count();
std::cout << duration;
return 0;
}
This will measure the duration of the function.
NOTE: You will not always get the same timing for a function. This...
Convert a float64 to an int in Go
...
Such casts have a problem in Go that can be unexpected (at least if you come from Java): "In all non-constant conversions involving floating-point or complex values, if the result type cannot represent the value the conversion suc...
Safe (bounds-checked) array lookup in Swift, through optional bindings?
..., to clarify the situation: b contains a value and the value is nil. If we casted automatically to Int?, we would loose the information, if we got a hit or a miss in the array, which might be necessary in some circumstances. I would rather debate, if Swift could get rid of automatically casting valu...
MIN and MAX in C
... macro from doing such potentially dangerous type promotions, a final type cast to the intended type was used.
Rationale
We want both parameters to the macro to be of the same type. If one of them is of a different type, the macro is no longer type safe, because an operator like ?: will yield impl...
How to update PATH variable permanently from Windows command line?
...rentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the string "Environment". This allows applications, such as the shell, to pick up your updates.
Note that your application will need elevated admin rights in order to be ab...
How to unit test abstract classes: extend with stubs?
... Oh no.. another tenet I'm gong to have to rethink! Thanks (both sarcastically for now, and non-sarcastically for once I have assimilated it and feel like a better programmer)
– Martin Lyne
Mar 18 '13 at 10:12
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When do you use the “this” keyword? [closed]
...e (struct) value.
To invoke an extension method on the current instance
To cast itself to another type
To chain constructors defined in the same class
You can avoid the first usage by not having member and local variables with the same name in scope, for example by following common naming conventi...