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When to use virtual destructors?
...Here, you'll notice that I didn't declare Base's destructor to be virtual. Now, let's have a look at the following snippet:
Base *b = new Derived();
// use b
delete b; // Here's the problem!
Since Base's destructor is not virtual and b is a Base* pointing to a Derived object, delete b has undefin...
How to correctly save instance state of Fragments in back stack?
...e also been coding my apps with this expected behavior for quite some time now.
– Ricardo
Mar 28 '15 at 23:32
1
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What are the barriers to understanding pointers and what can be done to overcome them? [closed]
...implified. There's more overhead and a lot more details you would
need to know if you need to deal with memory on a low-level basis. However, for the
intents of explaining memory and pointers, it is accurate enough.
Let's assume the THouse class used below looks like this:
type
THouse = clas...
Simple explanation of MapReduce?
...rite it like this
A = [7, 8, 9]
sum = A.reduce( 0, (x, y) => x + y )
Now it's a little confusing why there are 2 arguments (0 and the function with x and y) passed. For a reduce function to be useful, it must be able to take 2 items, compute something and "reduce" that 2 items to just one sing...
When to use thread pool in C#? [closed]
...d tasks.
Normally a pool consists of 2 threads per processor (so likely 4 nowadays), however you can set up the amount of threads you want, if you know how many you need.
Edit: The reason to make your own threads is because of context changes, (thats when threads need to swap in and out of the pr...
How to convert a DOM node list to an array in Javascript?
...obj[i];
}
return array;
}
UPDATE:
As other answers suggest, you can now can use in modern environments the spread syntax or the Array.from method:
const array = [ ...nodeList ] // or Array.from(nodeList)
But thinking about it, I guess the most common use case to convert a NodeList to an Ar...
WAMP error: Forbidden You don't have permission to access /phpmyadmin/ on this server
...
The Put Online option is now unavailable. To enable it, Right click on the Wamp Icon > Wamp settings > Check on the Menu item: Online/Offline, when you now left click on the icon, the 'Put Online' option will be available
–...
How to find the size of localStorage
...n("\n"));
P.S. Snippets are updated according to request in the comment. Now the calculation includes the length of the key itself.
Each length is multiplied by 2 because the char in javascript stores as UTF-16 (occupies 2 bytes)
P.P.S. Should work both in Chrome and Firefox.
...
Who is calling the Java Thread interrupt() method if I'm not?
...ly should not call System.exit(). (Your application does not necessarily know why it was interrupted, and it certainly does not know if there are other threads that need to be interrupted by the framework.)
On the other hand, if your code is not designed to run under the control of some framewor...
Best way to merge two maps and sum the values of same key?
...
The shortest answer I know of that uses only the standard library is
map1 ++ map2.map{ case (k,v) => k -> (v + map1.getOrElse(k,0)) }
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