How to convert 2's complement to its corresponding signed counterpart natural to the machine?
Efficient unsigned-to-signed cast avoiding implementation-defined behavior
I can never figure out whether I should use who and whom. Most people use who for both colloquially, but some people say this is not correct.  What’s the rule for using who and whom correctly? I recently upgraded to 12.04 from 11.10 and since upgrading have been unable to log in to my user profile. The upgrade went okay and I can login to a guest session fine but whenever I try to login to my profile, after entering my password, I just return to the login screen.  I've changed my password in Root (passwd &lt;username&gt;) and can log in to tty1 with no issues, it's just in GUI I'm having problems.  I'm using a HP dv7 laptop, 32-bit Ubuntu install, Intel® Core™2 Duo CPU P7350 @ 2.00GHz × 2, Nvidia graphics.  Any help would be appreciated. How can I respawn the Ender Dragon? Why does ( exit 1 ) not exit the script? Why can't a single photon produce an electron-positron pair? In reading through old course material, I found the assignment (my translation):     Show that a single photon cannot produce an electron-positron pair, but needs additional matter or light quanta.   My idea was to calculate the wavelength required to contain the required energy ($1.02$ MeV), which turned out to be $1.2\times 10^{-3}$ nm, but I don't know about any minimum wavelength of electromagnetic waves. I can't motivate it with the conservation laws for momentum or energy either.  How to solve this task? Hide deleted answers with certain characteristics Today I exceeded 10K reputation on Stack Overflow, and I see deleted answers.  I am now faced with pages like  where half the answers are "deleted."    Among these are many non-answers deleted by diamond moderators, and a self-deleted answer deleted on Nov 25 '09.  I find this very distracting, especially in my chosen sort order of "oldest" where these deleted answers are NOT displayed at the bottom.  I wish to be able to hide deleted answers based on combinations of characteristics such as:   age since deletion deleted-by-owner deleted by diamond moderators zero undelete votes   This would be a setting every user could enable for himself.    Here are HTML excerpts that may be useful for userscript filtering.  This shows the code that appears for a moderator deletion, as well as the date stamp.  &lt;div class="deleted-answer-info"&gt;deleted by &lt;a href="/users/10936/dori"&gt;Dori&lt;/a&gt;&lt;span class="mod-flair" title="moderator"&gt;♦&lt;/span&gt; &lt;span title="2011-06-26 09:13:34Z" class="relativetime"&gt;Jun 26 at 9:13&lt;/span&gt;&lt;/div&gt;   Here is the same class for deleted by owner:  &lt;div class="deleted-answer-info"&gt;deleted by owner &lt;span title="2009-11-25 19:12:11Z" class="relativetime"&gt;Nov 25 '09 at 19:12&lt;/span&gt;&lt;/div&gt; How to typeset the symbol “^” (caret/circumflex/hat) I need to display the symbol '^'  d &lt;- dist(fascores, method = "euclidean")^2   How do I do that? There are several Q&amp;A threads that explain how to download youtube videos using the terminal.  However, I would also like to learn how to extract the video's soundtracks as MP3 files--also using only the terminal.  Answers briefly explaining how to use youtube-dl or other similar utilities before explaining how to extract the MP3 would be ideal for the sake of having all the information in one place--even though this aspect has been covered in other posts. Network button missing gone from Nautilus? I'm using Ubuntu 16.04.3 LTS.  I remember having a link in Nautilus that I used to browse network shares with in the past. I don't remember exactly but I think it was "Windows network" or "Browse network".  Now I can't find this on my current installation, there's only "Connect to server", but this is not what I want. Is there a way to put that link there? Preserving order with LINQ I use LINQ to Objects instructions on an ordered array.  Which operations shouldn't I do to be sure the order of the array is not changed? Disable App Update Notifications on OSX? The various modern revolutions in physics, in psychology, in politics, even in literary style, have not escaped his intelligent notice, but they can scarcely be said to have influenced him deeply.    Could you please explain the following?  They can scarcely be said to have influenced him deeply.  Or, I can not understand such a structure like the following:  In contrast, prices set by a central planner are necessarily arbitrary, since there is no standard against which they can be said to be correct or incorrect. d'oh! What is $dx$ in integration? When I was at school and learning integration in maths class at A Level my teacher wrote things like this on the board.  $$\int f(x)\, dx$$  When he came to explain the meaning of the $dx$, he told us "think of it as a full stop".  For whatever reason I did not raise my hand and question him about it.  But I have always shaken my head at such a poor explanation for putting a $dx$ at the end of integration equations such as these.  To this day I do not know the purpose of the $dx$.  Can someone explain this to me without resorting to grammatical metaphors? How to use hook_node_presave to change field's value Basically, I want to put first name &amp; surname together into $node->field_par_contact_name  But it gives me warning. (See below)   function partnership_node_presave($node) {   if($node->type == 'partnership') {     $first_name = $node->field_par_contact_first_name['und'][0]['name'];     $surname = $node->field_par_contact_surname['und'][0]['name'];      // https://drupal.org/project/field_hidden     // Hidden variable     $node->field_par_contact_name['und'][0]['value'] = $first_name. ' '. $surname;      // Warning after save: array_flip(): Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->load() (line 173 of .../drupal-7.23/includes/entity.inc   } }   Updated, please see image: How to add a program as a startup application from a terminal? I am using Ubuntu 12.04 and I know the GUI way to maintain the startup program list but now I want to find out the way to add/remove startup applications using a command line interface (CLI). Can hard drives fully utilize SATA III? My motherboard currently supports both SATA II and III (3 Gb/s and 6Gb/s respectively), but after reading some online, it seems as though connecting a HDD to the 6 Gb/s is pretty much pointless. If this is the case I'm going to leave my two SATA III ports open for something that can actually use it (which at this point I'm not really sure what can).  This is part of an article I read:     In terms of everything else, we saw basically no difference from the same single drive being plugged into a SATA 6Gb/s or SATA 3Gb/s port. All of this is obviously due to the hard drive not being able to actually take advantage of the 6Gb/s bus.   from . It is quite easy to show that for every prime $p$ and $0&lt;i&lt;p$ we have that $p$ divides the binomial coefficient $\large p\choose i$; one simply notes that in $\large \frac{p!}{i!(p-i)!}$ the numerator is divisible by $p$ whereas the denominator is not (since it is a product of numbers smaller than $p$ and $p$ is prime).  My problem is with generalizing this argument for $q=p^n$. I'm looking for the most elegant and simple way to prove that $p$ still divides $\large q\choose i$. Is it possible to search for down voted questions? Would the latter be an issue with the funding body, when the project proposal and budget only covers the expenses for hiring one postdoc? Note: it is the supervisors who got the grants, not the postdocs themselves. With slapd.conf you could globally disable anonymous binding and require authentication with the following static directives:  disallow bind_anon require authc   How can I achieve the same global settings, but using the new cn=config live configuration method?