For Strings you have to use equals to compare them, because == only compares the references.  Does it give the expected result if I compare chars with == ?    I have seen similar questions on stackoverflow, E.g.      However, I haven't seen one that asks about using == on chars.
I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?
Resolving ambiguous overload on function pointer and std::function for a lambda using + cron job schedule I have 4 servers with Debian Wheezy OS. I have Apticron installed that informs me about updates. Debian updates are realized so often that when I finish to update the last of 4 servers I get new email about new updates on the first server. I try to update all servers when I get a notification but I never know if there is a need to reboot the servers. I have read that if the directory "/var/run" contains file "reboot-required" I have to reboot the server. But I never have seen this file in "/var/run". How can I know when reboot is required? I don't want reboot my servers every time when I install new updates if it's not needed.  I understand that if I update PHP or MySQL, etc I don't need to reboot the server but updates usually contain many "lib...".  Below are 9 updates (I have received this week).  krb5-locales 1.10.1+dfsg-5+deb7u3 libdbus-1-3 1.6.8-1+deb7u6 libgssapi-krb5-2 1.10.1+dfsg-5+deb7u3 libk5crypto3 1.10.1+dfsg-5+deb7u3 libkrb5-3 1.10.1+dfsg-5+deb7u3 libkrb5support0 1.10.1+dfsg-5+deb7u3 libruby1.8 1.8.7.358-7.1+deb7u2 libxml2 2.8.0+dfsg1-7+wheezy3 ruby1.8 1.8.7.358-7.1+deb7u2   I have no idea what is "libkrb,libgssapi", etc. How can I detect if reboot is needed? Please do not suggest to install UnattendedUpgrades to let the servers update automatically because this can cause websites going offline if something updates not correct. I'm planning to fly from Ulaanbaatar to Melbourne via Seoul (and Kuala Lumpur).  However, can I actually enter South Korea using this visa waiver? I'm hoping to meet a friend there for a few hours before flying. Also, would traveling via Malaysia affect this policy?  Transit tourists bound for another country Eligible countries  Applicable to all countries (save for Macedonia, Cuba, Syria, Sudan and Iran) that are not granted visa-free entry into Korea.  Applicable to…  Those with a visa (excluding Japanses Group Visa, excluding e-visa) or a re-entry permit for U.S., Japan, Canada, Australia, or New Zealand (5 countries) and traveling to any one of those countries through Korea.  Those traveling from any one of the five countries mentioned above, whose final destination is not Korea.  However, please note that the first bullet points are not applicable to those travelling to/from Guam and Saipan, which are unincorporated territories of the United States.   Requirements  Must have a confirmed onward flight ticket for departure within 30 days after entering Korea, in addition to having no record of criminal offence in the five countries mentioned above. (This question is only as reference, I will add the answer myself)  Suddenly the search in the expl3 documentation interface3.pdf no longer works. As an example searching for "divis" gives this as the first hit:    In sumatra there is no problem, other files (e.g. source3.pdf) works fine. What could be the reason?) Why does Oracle 9i treat an empty string as NULL? Installing Autodesk Maya on Ubuntu is possible, but can be a bit challenging.  Assuming that one already has the required specs and a solid graphics card driver installed, how can it be done? Design review - RGB LED color mixer using PWM Book identification about boy who gets computer zapped into head I remember this book from 15+ years ago about a normal boy who was working on his computer (replacing the motherboard maybe?) and he touched something and got zapped. When he came to he came to realize that the computer shocked itself into his head.   Cut to being the hero sometime down the line and maybe saving someone who was kidnapped? Or was kidnapped himself and had to get out of it using the computer?  I don't know why it's in my head all of the sudden but Google isn't helping me at all! I have B1/B2 Visa. Can I travel for Business trip to US with this Visa? The sine inequality $\frac2\pi x \le \sin x \le x$ for $0<x<\frac\pi2$ In a Poisson model, what is the difference between using time as a covariate or an offset? I recently discovered how to model exposures over time using the log of (e.g.) time as an offset in a Poisson regression.  I understood that the offset corresponds to having time as covariate with coefficient 1.  I'd like to better understand the difference between using time as an offset or as a normal covariate (therefore estimating the coefficient). In which situation should I want to use one method or the other?  UPGRADE: I don't know if it is interesting, but I ran a validation of the two methods using randomly split data repeated 500 times and I noticed that using the offset method leads to a larger test error. Paper status changed to “Decision in Process” rapidly after initial submission Upgrading my Wubi 11.04 to 11.10 I want to upgrade my current Wubi installation (Ubuntu 11.04) to Ubuntu 11.10. Is this possible to do inside Wubi? Or do I have delete Wubi from Windows, therefore deleting my current Ubuntu installation; and then install 11.10 via the Wubi installer?  Thanks Is there any evolutionary/physiological advantage to multi-lateral symmetry? Just wondering ; I get the impression a large number of multicellular organisms are multi-lateral in their physical structure. Why would evolution/mutation have retained multi-lateral symmetry in an organism? What advantage/s does symmetry provide an organism?  EDIT:  By multi-lateral symmetry I mean at-least bi-lateral symmetry (as in the case of many beings such as elephants, crabs and fishes), but perhaps more than bi-lateral too (starfish come to mind)  END EDIT: How Does The Debugging Option -g Change the Binary Executable? When writing C/C++ code, in order to debug the binary executable the debug option must be enabled on the compiler/linker.  In the case of GCC, the option is -g.  When the debug option is enabled, how does the affect the binary executable?  What additional data is stored in the file that allows the debugger function as it does? tables with lots of columns I have a table that lists various attributes of an individuals personal development plan; objective, time to complete objective, comments etc. The table is editable so the user can directly add comments without having to go to an intermediate form. The problem is that the client wants to add more columns and this is messing up the visual display.   The alternatives I have are:   allowing columns to expand out on click keeping essential attributes in table, rest in 'advanced edit option form' or somesuch I don't know - have you any ideas?   One more thing to add: I think the addition of extra columns is based on user feedback ...  edit: here is what I have gone for change thickness median line geom_boxplot() how does the circuit of a basic Variable speed electric drill work? i am trying to 'automate' the control of an electric drill motor that im taking from a garden variety Variable Speed drill (from Harbor Freight)  it has a universal AC motor which I basically undertand and a DPDT switch to reverse direction and a triac citcuit to vary speed    Question 1 . i see 4 wires going to the 'field/Stator coil(s)'. Are there 2 seperate field/stator coils here? is this to provide low/high power.  I think in theory , you only need 1 coil with 2 wires and that coil is wired in series with the brushes... is that right?   how does this circuit work with 2 coils.  Question 2 . how does this variable speed circuit work.  is the wiring diagram correct (it doesnt show a variable resistor and it doesnt show what drives the control input of the traic? why are there two switches in the thing? does switch 2 close at high speed and thus shunt around the triac?  please see the attached 4 diagrams Is static HTML the fastest? I have been researching several different techniques to deliver web content fast, like nginx and node.js.  When it comes down to performance optimization http expires headers and gzip come to mind. After that come common techniques like sprites and CDNs etc.  But I am wondering.  What would be the very fastest technique to load a website?  Is static html the very fastest that can be? Or is there something else even faster?