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Why can't I forward-declare a class in a namespace using double colons?
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Because you can't. In C++ language fully-qualified names are only used to refer to existing (i.e. previously declared) entities. They can't be used to introduce new entities.
And you are in fact "reopening" the namespace to declare new entities. If the class Class is l...
How to position a div in the middle of the screen when the page is bigger than the screen
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just add position:fixed and it will keep it in view even if you scroll down. see it at http://jsfiddle.net/XEUbc/1/
#mydiv {
position:fixed;
top: 50%;
left: 50%;
width:30em;
height:18em;
margin-top: -9em; /*set to a negative number 1/2 of your height*/
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One or more types required to compile a dynamic expression cannot be found. Are you missing referenc
...dio and reopening the project fixed it more long-term, so that's an option if this situation occurs while Microsoft.CSharp is already referenced.
Maybe restarting the IDE as a first step seems trivial, but here's a reminder for people like me who don't think of that as the first thing to do.
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How to find all serial devices (ttyS, ttyUSB, ..) on Linux without opening them?
...v/serial/by-id/
total 0
lrwxrwxrwx 1 root root 13 2011-07-20 17:12 usb-Prolific_Technology_Inc._USB-Serial_Controller-if00-port0 -> ../../ttyUSB0
flu0@laptop:~$ ls /dev/serial/by-path/
total 0
lrwxrwxrwx 1 root root 13 2011-07-20 17:12 pci-0000:00:0b.0-usb-0:3:1.0-port0 -> ../../ttyUSB0
This...
Android getting value from selected radiobutton
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In case, if you want to do some job on the selection of one of the radio buttons (without having any additional OK button or something), your code is fine, updated little.
public class MainActivity extends Activity {
@Override
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Deleting Objects in JavaScript
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The delete operator deletes only a reference, never an object itself. If it did delete the object itself, other remaining references would be dangling, like a C++ delete. (And accessing one of them would cause a crash. To make them all turn null would mean having extra work when deleting or ext...
Where do I find the current C or C++ standard documents?
...99, C++98, C++03 will be hard to find for purchase from a standards body. If you need an old revision of a standard, check Techstreet as one possible source. For example, it can still provide the Canadian version CAN/CSA-ISO/IEC 9899:1990 standard in PDF, for a fee.
Non-PDF electronic versions of...
Regex empty string or email
...can't handle it anyway. Try to find a library routine for matching them. If you only want to solve the practical problem of matching an email address (that is, if you want wrong code that happens to (usually) work), use the regular-expressions.info link someone else submitted.
As for the empty st...
What are the main disadvantages of Java Server Faces 2.0?
... the relative steep learning curve when you don't have a solid background knowledge about basic Web Development (HTML/CSS/JS, server side versus client side, etc) and the basic Java Servlet API (request/response/session, forwarding/redirecting, etc), no serious disadvantages comes to mind. JSF in it...
How to percent-encode URL parameters in Python?
...e that changes to Python since this answer was published mean that this is now a legacy wrapper. From the Django 2.1 source code for django.utils.http:
A legacy compatibility wrapper to Python's urllib.parse.quote() function.
(was used for unicode handling on Python 2)
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