What is the difference between virtual object and virtual image?
Virtual vs Real image
Can I enter the UK with a Schengen visa? Why does this code:  class A {     public:          explicit A(int x) {} };  class B: public A { };  int main(void) {     B *b = new B(5);     delete b; }   Result in these errors:   main.cpp: In function ‘int main()’: main.cpp:13: error: no matching function for call to ‘B::B(int)’ main.cpp:8: note: candidates are: B::B() main.cpp:8: note:                 B::B(const B&)   Shouldn't B inherit A's constructor?  (this is using gcc) PATH variable resets with reboot Thanking users who answered my question Quite often a number of users will give similar answers to one of my questions. Sometimes someone will give an answer that is interesting, but does not really help with my question.  In all cases, I feel a need to thank the people who answered my question. It isn't always appropriate for me to upvote every answer, and I can only accept one answer. Giving a "thanks" comment on every answer appears to be frowned upon.  So, what's the etiquette? When I dip a paper towel in a cup of water the water gets drawn up due to . How is this reconciled with conservation of energy, as it would seem on the surface that the potential energy of the system has gone up with no work being done? Proper capitalization of commonly used acronyms and initialisms Which browsers are officially supported by Stack Exchange?  Also, what else is needed in order to use every feature of the site? Show that one-sided limits always exist for a monotone function (on an interval) Show that one-sided limits always exist for a monotone function on an interval $[a,b]$.  Me attempt:  1) If a function is monotone on an interval $[a,b]$, then $f(a)\le f(x) \le f(b)$ for $x\in[a,b]$. Therefore if there exists left-hand (right-hand) limit of this function at a given point, then it must be finite. Now we must show that a both left-hand and right=hand limits exist. We use the fact that if we take a sequence $(x_n)\rightarrow c^{+} \in [a,b]$ then $f(x_n)$ is bounded and monotone and therefore it is convergent. I have a simple question but I am not sure on how to proceed. I would like to put 10 figures on the same page: a grid of 5 rows and 2 columns.  What should I type in order to have the figure inserted like this and with equal alignement/size ? Eventually with custom captions... ;) Some creatures have Magic Resistance:     The [...] has advantage on saving throws against spells and other magical effects.   We know from  that this works against Turn Undead, but does it work against Stunning Strike, Death Strike, Fey Presence, etc? How do we decide? terminal won't launch after install python 3.5 After I installed Python 3.5 and ran the commands below, my terminal and many other programs won't launch any more.  cd /usr/bin sudo rm python3 sudo ln -s python3.5 python3    How can I restore the default Python version again to fix these problems? Relativity and Galaxy Rotation Speed Why does `last` show '{' and '|' in the TTY field? How to prove $ \prod_{d|n} d= n^{\frac{\tau (n)}{2}}$ How to partition for Windows/Ubuntu dual boot on same SSD I have a 500GB SSD in which i would like to have both Windows and Ubuntu. My plan is to have something similar to this: Windows 8.1 and ubuntu 14.04 Uefi boot   an efi partition (created by windows installer) which will have Grub as bootloader 150GB ntfs for Windows 15GB ext4 for Ubuntu (root) 35GB ext4 for Ubuntu (home) ~8-16GB swap for Ubuntu (I have 16GB RAM) ~284-292GB ntfs for Data shared for both Windows and Ubuntu   My current setup is   200GB ntfs Windows 300GB ntfs for Data   I plan to shrink both the Windows and the data partiton in order to achieve my desired plan.  My questions:   Does the order of partitions matter? Does it matter if the ubuntu partitions are not at the end/beggining of the drive? Does the swap partition behaves better if its the last/first partition? Can I use the shared NTFS Data partition between windows and ubuntu without encountering problems? Do I have enough space for my ubuntu /home partition (thinking that I'll have access to the ntfs shared partition)?   Edit: Laptop, Asus N56jr, i7, 16Gb Ram, SSD samsung 850 evo 500gb  Windows 8.1 and Ubuntu 14.04 Comparing two strings in Bash I have the following if block in my bash script:  if [ ${PACKAGENAME} -eq kakadu-v6_4-00902C ]; then   echo "successfully entered if block!!" fi   The script execution is not entering my if block even though $PACKAGENAME is equal to kakadu-v6_4-00902C. What am I doing wrong? Are there concerns with doing a generalized additive model with a smoothing term of multiple variables? In R, usually one performs a generalized additive model like so:  library(mgcv) x &lt;- gam(depvar ~ s(indvar1) + s(indvar2) + parametricvar)   Say I want to explore the non-parametric interaction of indvar1 and indvar2.  Is the following kosher?  x &lt;- gam(depvar ~ s(indvar,indvar2) + parametricvar) If I start a Google+ Hangout, is there anyway to send my friends a link directly to that Hangout post? I couldn't find any options.   So I have to send people a link to my profile, and let them click on the join hangout button. I prefer not to do that since the hangout post may be buried by my other updates. Is Bezout's lemma enough to confirm the GCD of a number. Is Bezout's lemma enough to confirm the GCD of a number?  So suppose we have $$ax+by=z$$ does this mean $$\gcd(a,b)=z$$ Launch iOS app from sites Can we add functionality to the mobile site to view the page in the SE iOS app? It could be through  or a link at the bottom where the download link is.        I really don't care which, but right now there's just no way to do it.