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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...
Facebook Android Generate Key Hash
...ate a new certificate when you next try to build a debug package.
Let me know if that works.
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Using global variables in a function
...bal variables are so dangerous, Python wants to make sure that you really know that's what you're playing with by explicitly requiring the global keyword.
See other answers if you want to share a global variable across modules.
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Disabling Chrome cache for website development
...iller that clears the cache on every page load.
Chrome Store Link (free)
(Now without malware!)
Now my mock json, javascript, css, html and data refreshes every time on every page load.
I never have to worry if I need to clear my cache.
There are about 20 cache cleaners for Chrome I found, but ...
Plotting time in Python with Matplotlib
...ve returns a list with one object of type: matplotlib.lines.Line2D object. Now how do I use this to show the graph?
– Arindam Roychowdhury
Jul 20 '17 at 6:59
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Differences between fork and exec
...d process (parent) as its parent PID (PPID). Because the two processes are now running exactly the same code, they can tell which is which by the return code of fork - the child gets 0, the parent gets the PID of the child. This is all, of course, assuming the fork call works - if not, no child is c...
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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What's wrong with overridable method calls in constructors?
...s.levels = levels;
this.isAdjustable = isAdjustable;
}
}
And now you can do any of the following:
new Telescope("X/1999");
new Telescope("X/1999", 13);
new Telescope("X/1999", 13, true);
You can't, however, currently set only the name and isAdjustable, and leaving levels at default....
How to thoroughly purge and reinstall postgresql on ubuntu? [closed]
...ake sure PostgreSQL isn't running. ps -C postgres should show no results.
Now run:
apt-get --purge remove postgresql\*
to remove everything PostgreSQL from your system. Just purging the postgres package isn't enough since it's just an empty meta-package.
Once all PostgreSQL packages have been r...
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...