Can we declare an interface class by making all the methods abstract using the keyword ‘abstract’ in a class in C++?
How do you declare an interface in C++?
Case insensitive 'Contains(string)' Is there a way to make the following return true?  string title = "ASTRINGTOTEST"; title.Contains("string");   There doesn't seem to be an overload that allows me to set the case sensitivity.. Currently I UPPERCASE them both, but that's just silly (by which I am referring to the  issues that come with up- and down casing).  UPDATE This question is ancient and since then I have realized I asked for a simple answer for a really vast and difficult topic if you care to investigate it fully. For most cases, in mono-lingual, English code bases  answer will suffice. I'm suspecting because most people coming here fall in this category this is the most popular answer.  answer however brings up the inherent problem that we can't compare text case insensitive until we know both texts are the same culture and we know  what that culture is. This is maybe a less popular answer, but I think it is more correct and that's why I marked it as such. I am rendering my scene with only one sample but all the renders of the same picture have a different seed value. How can I combine them correctly? I wrote a java-program that loads all the images and takes the average pixel color for each pixel of the images. Is that a correct way of combining the images? It doesn't reduce the noise very much so I am not happy with it. What can I do? Accepted answer appearing below top voted Why is list initialization (using curly braces) better than the alternatives? /testfor for item enchantment What I have now is:  /testfor @a {SelectedItemSlot:0,Inventory:[{Slot:0b,id:"diamond_pickaxe"}]}   How can I use the /testfor command to test a specific slot for a specific item that is enchanted? Why does chmod succeed on a file when the user does not have write permission on parent directory? I am trying to understand file/dir permissions in Linux.  A user can list the files in a directory using   cd test ls -l    Even if the user issuing above commands does not have read, write or execute permission on any of the files inside the test directory, still he can list them because he/she has read permissions on the test directory.   Then why in the following scenario user B can change permissions of a file he owns but does not have write permissions of the parent directory?  User A, makes a test directory and gives other users ability to write in it:  mkdir test chmod o+w test   User B, creates a file in test folder.  cd test touch b.txt   User A removes write permission of others from the directory  chmod o-w test   User B, can successfully change permissions, even though permissions are part of directory and this user does not have write permission on the parent directory of the file he owns  chmod g-r b.txt   why does chmod not fail since the user cannot modify the directory which has the file information - permissions etc? Rich Snippets not working (and working at the same time?) We have an eCommerce site, and we have had rich snippets implemented (in JSON-LD) since January/February this year (2015). I have read multiple sources (including the Google documentation) and there seem to be three possibilities why they are not showing:   Not enough time has passed (4-12 weeks seems to be the common time quoted) The markup is wrong Google have decided not to show the data   I can rule out the first given the amount of time. The second I am fairly confident is not the case as I have used multiple testing tools. As for the third … well that's anyone's guess (although the study  suggests that MOST shops should be successful).  A strange note is that the rich snippets do not show on a regular search for our ranking keywords (we rank #1 for a few and page 1 for the majority). However the rich snippets DO show when we search for a ranking keyword + site:www.fridgefreezerdirect.co.uk as show here:    I have done this in an incognito window in the browser and using a VPN with the same results.  Can anyone suggest anything we can do or reasons this may be? I'm running a VPS of a german provider and want to switch from Ubuntu to CentOS. There I tried to install firewalld (was not preinstalled), but it always fails with the error  ERROR: Failed to load nf_conntrack module: modprobe: ERROR: could not find module by name='nf_conntrack' modprobe: ERROR: could not insert 'nf_conntrack': Function not implemented modprobe: ERROR: Error running install command for nf_conntrack modprobe: ERROR: could not insert 'nf_conntrack': Operation not permitted   Obviously the nf_conntrack kernel module was not found. Since this is a VPS, I cannot tinker with the kernel modules. On the support site of my provider I found a list of available kernel modules, for example:  ip_conntrack_netbios_ns ipt_conntrack    ip_conntrack    ip_conntrack_ftp    ip_conntrack_irc   Since nf_conntrack is not listed here, does that mean, that I cannot use firewalld? Is it possible to run it without this module?  I guess I could use iptables, if I wanted to (it seems to run correctly). But as I have more experience with firewalld, I would like to stick with it.    CentOS Linux release 7.7.1908 (Core)  uname -a: Linux xxxxxx.xxxxxxxx.xxx 3.10.0-042stab140.1 #1 SMP Thu Aug 15 13:32:22 MSK 2019 x86_64 x86_64 x86_64 GNU/Linux Proving that if $G/Z(G)$ is cyclic, then $G$ is abelian Possible Duplicate:             If $G$ is a group and $Z(G)$ the center of $G$, show that if $G/Z(G)$ is cyclic, then $G$ is abelian.  This is what I have so far:  We know that all cyclic groups are abelian. This means $G/Z(G)$ is abelian.  $Z(G)= \{z \in G \mid zx=xz \text{ for all } x \in G \}$.  So $Z(G)$ is abelian.    Is it sufficient to say that since $G/Z(G)$ and $Z(G)$ are both abelian, $G$ must be abelian? List manipulation: position & max value combination Food in the Star Wars Universe? Can someone please confirm the following? I have a C1/D visa. I worked as a flight attendant (currently unemployed) and entered the US numerous times, and also visited Mexico in December 2017.  I am planning on visiting Mexico again for 3 weeks in due course. Will the C1/D allow for me to transit in the US and visit Mexico or do I need a B1/B2 visa? I had issues with CBP before as it seems to be a very grey area.  According to the Mexican Consulate in South Africa, the type of visa is irrelevant. As long as it is multiple-entry, I am good to go.  Can someone please confirm, as I cannot get a solid answer from anyone?  Thank you! Logical explanation why exponentiation operation is not commutative and associative Considering Peano axioms we'll define addition, multiplication and exponentiation operations.  We can then prove that addition and multiplication operations are commutative and associative. The proof for addition operation is pretty straightforward but for for multiplication it a bit more difficult. For example, to prove associativity, we have to prove distributivity first.  Moreover, for the definition itself it is not obvious that commutativity should take place, because the definition is not symmetric.  $a \cdot 0 := 0$  $a \cdot S(b) := a \cdot b + a$  Here $S(b)$ is the "next" function from Peano axioms  This definition is not symmetric with respect to $a$ and $b$, so commutivity is not obvious.  For exponentiation operation neither commutivity nor associativity take place. And I am very curious about the logical explanation why that happens  NOTE: The explanation I am looking for is somehow similar to a Abel–Ruffini theorem which explains WHY there is no an algebraic solution for a general polynomial equation I'm new to blender and trying to model the blade of my helicopter and can't figure out how to make an edge curved (for the red tip and selected edge). The object is a plane, with one loop cut. I attempted making a bevel Ctrl B, but nothing happens (A dotted line appears attached to the cursor, moving does nothing, left-clicking does nothing).  also I cant add a curve modifier, just says its disabled. What is the correct way to model this? What is a Vanilla JS or jQuery solution that will select all of the contents of a textbox when the textbox receives focus? In this kind of sentence the second half is an inversion of the first half. Is it a rhetorical artífice? What kind? Show some indication that account is banned from asking new questions I am not an expert of random forest but I clearly understand that the key issue with random forest is the (random) tree generation. Can you explain me how the trees are generated? (i.e. What is the used distribution for tree generation?)  Thanks in advance ! Push Notification Badge Count Not Updating Why is my camera limited to a shutter speed of 1/250th when the flash is up? Sometimes in bright backlight and with large aperture (f2.8) I want flash at high shutter speeds.  But when I pop the flash up on D7000 it caps the shutter speed to 1/250th, which overexposes the shots and makes everything look like a nuclear bomb just went off.  What's the logic behind the limiting of the shutter speed when using flash? Is there anything I can do to get flash  + faster shutter speeds?