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What are the advantages of using nullptr?
This piece of code conceptually does the same thing for the three pointers (safe pointer initialization):
7 Answers
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Big O, how do you calculate/approximate it?
..., but be warned that this topic takes my students a couple of months to finally grasp. You can find more information on the Chapter 2 of the Data Structures and Algorithms in Java book.
There is no mechanical procedure that can be used to get the BigOh.
As a "cookbook", to obtain the BigOh from ...
Computational complexity of Fibonacci Sequence
...ll have depth n and intuitively figure out that this function is asymptotically O(2n). You can then prove your conjecture by induction.
Base: n = 1 is obvious
Assume T(n-1) = O(2n-1), therefore
T(n) = T(n-1) + T(n-2) + O(1) which is equal to
T(n) = O(2n-1) + O(2n-2) + O(1) = O(2n)
However, as ...
jQuery: select an element's class and id at the same time?
... yes you can specify a selector that has to match ID and class (and potentially tag name and anything else you want to throw in).
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What does enumerable mean?
...his condition is in place because objects have many more properties, especially from inheritance:
console.log(Object.getOwnPropertyNames(Object.prototype));
// ["constructor", "toString", "toLocaleString", "valueOf", "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable", /* etc. */]
Each of t...
Value Change Listener to JTextField
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Add a listener to the underlying Document, which is automatically created for you.
// Listen for changes in the text
textField.getDocument().addDocumentListener(new DocumentListener() {
public void changedUpdate(DocumentEvent e) {
warn();
}
public void removeUpdate(DocumentE...
CSS center text (horizontally and vertically) inside a div block
...al align".
Since they tend to be hacks or adding complicated divs... I usually use a table with a single cell to do it... to make it as simple as possible.
Update for 2020:
Unless you need make it work on earlier browsers such as Internet Explorer 10, you can use flexbox. It is widely supported...
Where should I put tags in HTML markup?
...ace to put the <script> tags and included JavaScript? I seem to recall that you are not supposed to place these in the <head> section, but placing at the beginning of the <body> section is bad, too, since the JavaScript will have to be parsed before the page is rendered compl...
Convert number to month name in PHP
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The recommended way to do this:
Nowadays, you should really be using DateTime objects for any date/time math. This requires you to have a PHP version >= 5.2. As shown in Glavić's answer, you can use the following:
$monthNum = 3;
$dateObj = DateTime::createFromFormat('!m',...
How to install packages offline?
... download a python package and it's dependencies from pypi for offline installation on another machine? Is there any easy way to do this with pip or easy_install? I'm trying to install the requests library on a FreeBSD box that is not connected to the internet.
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