Is it possible to use delete operator on class instance without new operator to deallocate memory? Like this:  Class myclass{public void hi{std::cout&lt;&lt;"hi\n";};}  myclass class1; delete &amp;class1; class1.hi(); //results in error   Thanks
Ignoring programming style and design, is it "safe" to call delete on a variable allocated on the stack?  For example:     int nAmount;    delete &amp;nAmount;   or  class sample { public:     sample();     ~sample() { delete &amp;nAmount;}     int nAmount; }
Normal subgroups of infinite symmetric group I recently took a course on group theory, which mentioned that the following proposition is equivalent to the continuum hypothesis: "The infinite symmetric group (i.e. the group of permutations on the set $\mathbb{N}$) has exactly 4 normal subgroups." Does anyone have any references or explanation for this? What is the standard team composition for a conquest game? I'm very new to Smite, and I'm wondering if there is some kind of standard team composition in high level play, comparable to the top, jungle, mid, dual lane meta in LoL.  What are the roles, and where should they go to start the game? Why is defragmentation unnecessary? How can I disassociate an account? I want to disassociate an account from the rest of my associated accounts. How can I do that?  The information in  doesn't seem to be relevant anymore, since I can't find this thing     Click the "Clear All Associations" button on the bottom of the Accounts page on your profile.   Every time I add or remove an email or OpenID from one site it propagates to the entire network. Group of order $8p$ is solvable, for any prime $p$ Consider the following question:     Show that a group $G$ of order $8p$ is solvable, for any prime $p$.   I am kind of stuck, but here are my first attempts:  I chose the series of subroups $G&gt;H_8&gt;H_4&gt;H_2&gt;H_1=\{e\}$ where $H_k$ has order $k$. All of these subgroups exist due to Sylow's Theorems. We have the quotients $H_8/H_4\cong H_4/H_2 \cong H_2/H_1 \cong \mathbb Z/2\mathbb Z$, so $G&gt;H_8\rhd H_4\rhd H_2\rhd H_1=\{e\}$. Only the factor $G/H_8 \cong \mathbb Z/p\mathbb Z$ is causing me a headache, because although its of prime order (and hence abelian) I don't know whether $H_8$ is normal in $G$ (unless $p=2$).  If $p\ne 2$, then the number $k$ of Sylow $2$-subgroups is $1$ mod $2$. Since $k$ divides $|G|$ we might have $k=1$ or $k=p$. If we had $k=1$ then $H_8$ would be the only Sylow $2$-subgroup (and hence normal in $G$). But how could we show this?  Or is there even an easier way to approach this problem?  $\ $  edit: I am going to try a different approach: The case $p=2$ is clear. When $p=3$ or $p=7$ the group has order 24 or 56 and since the smallest simple non-abelian group has order 60, the group must also be solvable in these exceptional cases (as Mariano pointed out).  In any other case we get a Sylow $p$-subgroup $H_p$ of order $p$, which is is normal in $G$. The quotient $G/H_p$ has order $8=2^3$; and prime power order implies solvable. So $G/H_p$ is solvable and $H_p$ is also solvable. And since the composition factors of $G$ are those of $H_p$ together with those of $G/H_p$, we conclude that $G$ is solvable iff $H_p$ and $G/H_p$ are solvable, which is the case. Hence $G$ is solvable if $|G|=8p$. $4x^2+1$ factors only into $4y+1$ primes Laptop water damage repair procedure I'd love some advice in repairing a water-damaged laptop.  My girlfriend spilled a glass of water on her Sony Vaio and now it doesn't turn on...at all...dead! What steps should I go through to work out where the problem is and which part(s) I'll need to replace?  I can't seem to find out what has happened by just looking at the circuit boards. I'm new to electronics but could buy relevant volt-meters etc. I'm just looking for a decent trouble-shooting guide. Can I check iPhone, iPad, Watch battery on Mac? My goal is to have battery status of other Apple device on my Mac (preferably on menubar). I'd like to have a glimpse of the battery status of my iPhone, iPad, Watch, and Airpods.  I'm a user of Bitbar and iStat menu, but I haven't found any widgets can wirelessly check other Apple device's battery status.  What I know is that I can click the Wi-Fi icon on menu bar and it will show my iPhone battery status. To show the percentage, I have to option + click the Wi-Fi icon and hover over my mouse on the iPhone hot spot section. It's pretty clunky, but I guess at least the API is there.  I am also open to third party apps which can let me see battery status across devices. Prove $-(-a)=a$ using only ordered field axioms I need to prove for all real numbers $a$, $-(-a) = a$ using only the following properties:     I tried by starting with P12 written using symbolic logic:  $\begin{align} \forall a,b \in P \to &amp; a \cdot b \in P \Leftrightarrow True \\ \forall a \in P \land \forall b \in P \to &amp; a \cdot b \in P \Leftrightarrow True \\ \lnot \left[ \left( \forall a \in P \right) \land \left( \forall b \in P \right) \right] \lor &amp; a \cdot b \in P \Leftrightarrow True \\ \exists a \notin P \lor \exists b \notin P \lor &amp; a \cdot b \in P \Leftrightarrow True \\ \end{align} \\ $  and played with evaluating it with $b = -1$, $-a$ and so on. But, felt this wasn't really a solution because the last symbolic logic statement above is ambiguous.  Not to mention--other than P12--I haven't used any of the axioms listed above whatsoever. ( And I've not bothered to prove any of the theorems of symbolic logic I have used. )  Can anyone give me a start on this problem?  Many thanks in advance.  Edit  Thank you, everyone! .  Best regards! Secretary problem - why is the optimal solution optimal? I have read about this problem:    But I want to see how it is proven that the "optimal" solution is indeed optimal. I understand how to prove that if the optimal solution is of the form "wait for $t$ candidates and then choose the next best one" then $t=n/e$ is optimal; but why is the best strategy of that form in the first place?  A complete proof is not required - a reference to a good text discussing this is good as well. I'm a bit annoyed with the typesetting of citations that biblatex deems "ambiguous". In the following example, I have two papers with the same first author, but a different second author in two different years. When citing in the main text, the second author is included before "et al", since biblatex deems these references to be ambiguous. However, the references were published in different years, so I cannot see why these are ambiguous. Is it possible to get these citations referenced using only the first author?  MWE  \documentclass{article}  \usepackage{filecontents} \usepackage[hyperref,style=authoryear,natbib=true,maxbibnames=10,maxcitenames=2,useeditor=false,url=false,useprefix,giveninits=false]{biblatex} \addbibresource{ref.bib}  \begin{filecontents}{jobname.bib} @book{author_book, title = {Book's title}, author = {Author, Some and Better, Some and Cetter, Some}, location = {The City}, publisher = {Publisher}, date = {2005}, } @book{author_book2, title = {Book's title}, author = {Author, Some and Getter, Some and Cetter, Some}, location = {The City}, publisher = {Publisher}, date = {2006}, } \end{filecontents}  \bibliography{jobname} % \bibliography{ref}  \begin{document} Hello world \citet{author_book} \citet{author_book2} \printbibliography \end{document} Issue with using ContactID as subscriber key in Marketing Cloud We have set up our Sales Cloud - Marketing Cloud integration where Contact ID is used as the subscriber key.  What we've noticed is when we have contact ID as the subscriber relationship on our sendable data extension, Marketing Cloud will reference contact ID on All Subscribers list and if data matches, it will send to the email address listed on All Subscribers and not to the one on the data extension.  This has caused us headaches for a number of reasons:   Email addresses always change so the one on All Subscribers is out-of-date. Whilst preference center can update a recipients address and write this back to All Subscribers that not how most addresses are updated by the user Email address is typically updated in Sales Cloud instance and migrated to Marketing Cloud either through imports or via synchronized data extensions.  It does not map directly to All Subscribers. Marketing Cloud users assume (and quite rightly) the address listed on the data extension is what will be used in the send. Not the one on All subscribers.   Anyone else experienced this? Any solution to resolve this issue? How to pass parameters to an alias? For bash script, I can use "$@" to access arguments. What's the equivalent when I use an alias? How do you handle "that that"? The double "that" problem Have you ever had a case where you felt compelled to include strange things like a double that in a sentence? If so, then what did you do to resolve this?  For me, I never knew whether it was acceptable grammar. However, what I did learn was that it was a logic distractor, could lead to confusion, and therefore should be reworded to avoid this. A diffeomorphism whose tangent map preserves dot products is an isometry. I'm having trouble solving the following problem.  If $F:\mathbb{R^3} \to \mathbb{R^3}$ is a diffeomorphism such that $F\ast$(the tangent map of $F$) preserves dot products, show that $F$ is an isometry. (Hint: Show that $F$ preserves lengths of curve segments and deduce that $F^{-1}$ does also.)  I'm trying to proceed as in the hint, but I'm stuck on the first step, showing the $F$ preserves lengths of curve segments. Moreover, how does showing that both $F$ and its inverse preserves length of curve segments show that it is an isometry. And how do I characterize the curve segments. I would appreciate any solutions, hints or suggestions. Why does a free-falling body experience no force despite accelerating? I need to enter the command line alone with no GUI to install the official NVIDIA drivers. I'm trying to get my computer to work over HDMI and someone on Youtube shows how but you have to be in the Nvidia settings program. Where did the name "Stack Exchange" come from? I get Stack Overflow (which I'm guessing was the first site?) and Super User, Code Review, and the other sibling site names make sense to me.  But I've never heard of a stack exchange before.  Is a stack exchange a real thing, or is this site's name a combination of Stack Overflow and an exchange of ideas? I am able to produce a standard length \sim with a tiny S above it, but I would like the \sim tilde to be longer (maybe one and half times as wide as a capital letter).  Any tips on how to change the width/length of \sim? What is the status icon that looks like a house? There is a strange icon that shows up in my status bar only when I'm at a certain restaurant. It looks like a cross between a house and wifi.   I suspect it might be a free wifi hotspot or something related to a nearby phone store, but I can't find any information about it in manual for my phone.  See the following screenshot: