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Why do we need virtual functions in C++?
...rats. Should you overload func() so it takes a Cat*? If you have to derive more animals from Animal they would all need their own func().
The solution is to make eat() from the Animal class a virtual function:
class Animal
{
public:
virtual void eat() { std::cout << "I'm eating g...
Grouping functions (tapply, by, aggregate) and the *apply family
...b c
1 3 91
sapply(x, FUN = sum)
a b c
1 6 5005
In more advanced uses of sapply it will attempt to coerce the
result to a multi-dimensional array, if appropriate. For example, if our function returns vectors of the same length, sapply will use them as columns of a matrix:
sa...
Difference between left join and right join in SQL Server [duplicate]
... Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
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What is wrong with using goto? [duplicate]
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I know this is an old post, but I thought I'd add one more use for goto. In SQR goto is commonly used as a 'continue' in a loop. Many database languages don't have continues in the language so they put a goto at the end of the loop and call it if they need to 'continue'.
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Can I see changes before I save my file in Vim?
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Why does Twitter Bootstrap Use Pixels for Font Size?
...ully coherent enough. I'll try to blog about these changes as they come up more, but I'm unsure how close 3.0 is and what that will all entail yet.
I would suggest anyone with strong feelings about this go and +1 this thread.
[Update] V3 roadmap oulined in V2.3 release blogpost makes no mention of ...
In Matplotlib, what does the argument mean in fig.add_subplot(111)?
...starts from 1 and increments row-first. See documentation of subplot() for more info.
– Christian Alis
Feb 2 '11 at 16:54
18
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How to check visibility of software keyboard in Android?
...otView.getHeight();
if (heightDiff > dpToPx(this, 200)) { // if more than 200 dp, it's probably a keyboard...
// ... do something here
}
}
});
Using a utility such as:
public static float dpToPx(Context context, float valueInDp) {
DisplayMetrics metrics = ...
Choosing between MEF and MAF (System.AddIn)
... in the flexibility of the types that you can send back and forth.
MEF is more like dependency injection with some additional benefits such as discoverability and ... (drawing a blank on this one). The degree of isolation that MAF has is not present in MEF. They are two different frameworks for tw...
Make Vim show ALL white spaces as a character
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