I have an error while running my c++ code using mingw in windows 10. The error is something like this : the procedure entry point __gxx_personality_v0 could not be located in the dynamic link library ----a.exe  I have no idea how to resolve that. I tried to google it but i could not find any solution.  Edit 1: I noticed that programs in a particular folder are not working. For other folders it is working fine.  Edit 2: I reinstalled MingW. But I am getting the error whenever i am using string data type in c++.
I've been getting this undefined symbol building with this command line:  $ gcc test.cpp Undefined symbols:   "___gxx_personality_v0", referenced from:   etc...   test.cpp is simple and should build fine.  What is the deal?
Why can't I do foreach (var Item in DataTable.Rows)? I am often interested in the installation triggers (postinst, postrm) or certain parts of packages (like /usr/share and /etc). Currently, I am running the next command to retrieve the source code:  apt-get source [package-name]   The downside is, this file is often much bigger than the binary package and does not reflect the installation tree.  Right now, I am downloading the packages through :      Download the actual file   This takes too long for me and as someone who really likes the shell, I would like to do something like the next (imaginary) command:  apt-get get-deb-file [package-name]   I could not find something like this in the . The most close I found was the --download-only switch, but this puts the package in /var/cache/apt/archives (which requires root permissions) and not in the current directory. Let $A,B \subset \mathbb{R}$. Show that $\sup(A \cup B) = \max\{\sup A, \sup B\}$   Here's what I did so far:  Let $\sup A, \sup B$, and $\sup (A \cup B)$ denote upper bounds of $A,B$, and $A \cup B$, respectively. If $x \in A$, then $x \le \sup A$. If $x \in B$, then $x \le \sup B$. In either case, $x \in (A \cup B)$. So either $x \le \sup A$ or $x \le \sup B$. In either case, $x \le \max \{\sup A, \sup B\}$. So $\max \{\sup A, \sup B\}$ is the upper bound of $A \cup B$, which means $\sup (A \cup B) \le \max\{\sup A, \sup B\}$.  I do not know if there's a better way to go at it, but all I did was show the inequality. Can I do this, and show the reverse inequality? If so, how can I go about doing that? Are wormholes really a valid shortcut to distant points in the universe? Lately I encountered a few times references to wormholes as a way to reach distant places in the universe in a short time. I have to admit I don't have a proper knowledge of the mathematics behind wormholes (although I won't mind a complete GR explanation in the answer, if necessary). All I know is that wormholes are usually compared to something analogous to a tunnel through the planet Earth to reach distant places in less time. The problem is, if I want to reach the other side of the planet I have to travel 20.000 km on its surface and "only" 12.000 km through its center. While the latter is surely shorter, it's still more than 50% of the initial value and this is the best-case scenario. For shorter distances, the difference becomes more and more negligible.  Now, I know enough of GR to understand that this explanation could be a simplification so extreme that any comparison makes little to no sense, but I'm curious to understand if the same problems arise for wormholes too. I don't really care if wormholes exist, are traversable by spaceships and both the crew and the vessel can survive the travel undamaged, I know they are still a theoretical construct and probably there is more than one formulation for it. What I'm really interested in is:   How much shorter will the travel be? I'm interested in Earth proper time, because if the reduction is only in the spaceship proper time, the we can achieve the same result "simply" by traveling closer to the speed of light. Does the amount of reduction in time depend on the distance between the endpoints? If so, it seems unpractical to travel to near stars through wormholes, if the spacetime geometry of our galaxy doesn't help somehow (local curvature should be higher than global curvature). Sometimes a suggested edit is  because of a concurrent direct edit that takes precedence.  Since this is no fault of the edit suggestor, such rejections should not count against the suggestor when counting .  Here are some examples where it happened: I went for B1 U.S. Visa at the U.S. Embassy in Delhi.   Interviewer: *Good Morning*. Me: *Good Morning* Interviewer: *What is your designation?* Me: *I am a Software Engineer.* Interviewer: *What is the name of your company?* Me: *It is XXX (I replied).* Interviewer: *What is the name of your client?* Me: *It is YYY (I replied).* Interviewer: *Have you ever been to U.S. before?* Me: *NO* Interviewer: *Have you ever been abroad before?* Me: *NO*   At this point he rejected my Visa with letter mentioning 214 (b) as the reason. I don't know why he actually rejected it.  But, I have decent 2+ years of experience with my company. And, I was going on a business meeting with the client. I would have come back after 2 weeks.  I don't know if re applying will help. Prove that $ \sum_{n=0}^\infty \frac{z^{2^n}}{1-z^{2^{n+1}}}=\frac{z}{1-z} $ Show that for $|z|&lt;1$, one have $$ \frac{z}{1-z^2}+\frac{z^2}{1-z^4}+\cdots+\frac{z^{2^n}}{1-z^{2^{n+1}}}+\cdots = \frac{z}{1-z} $$ and $$ \frac{z}{1+z}+\frac{2z^2}{1+z^2}+\cdots+\frac{2^k z^{2^k}}{1+z^{2^k}}+\cdots = \frac{z}{1-z} $$ Use the dyadic expansion of an integer and the fact that $2^{k+1}-1=1+2+2^2+\cdots+2^k$. How to compute the determinant of a tridiagonal matrix with constant diagonals? How to show that the determinant of the following $(n\times n)$ matrix  $$\begin{pmatrix} 5 &amp; 2 &amp; 0 &amp; 0 &amp; 0 &amp; \cdots &amp; 0 \\ 2 &amp; 5 &amp; 2 &amp; 0 &amp; 0 &amp; \cdots &amp; 0 \\ 0 &amp; 2 &amp; 5 &amp; 2 &amp; 0 &amp; \cdots &amp; 0 \\ \vdots &amp; \vdots&amp; \vdots&amp; \vdots &amp; \vdots &amp; \vdots &amp; \vdots \\ 0 &amp; \cdots &amp; \cdots &amp; 0 &amp; 2 &amp; 5 &amp; 2 \\ 0 &amp; \cdots &amp; \cdots &amp; \cdots &amp; \cdots &amp; 2 &amp; 5 \end{pmatrix}$$  is equal to $\frac13(4^{n+1}-1)$?    More generally:     How does one compute the determinant of the following  (where the three diagonals are constant)?      $$M_n(a,b,c) = \begin{pmatrix} a &amp; b &amp; 0 &amp; 0 &amp; 0 &amp; \cdots &amp; 0 \\ c &amp; a &amp; b &amp; 0 &amp; 0 &amp; \cdots &amp; 0 \\ 0 &amp; c &amp; a &amp; b &amp; 0 &amp; \cdots &amp; 0 \\ \vdots &amp; \vdots&amp; \vdots&amp; \vdots &amp; \vdots&amp; \vdots &amp; \vdots \\ 0 &amp; \cdots &amp; \cdots &amp; 0 &amp; c &amp; a &amp; b \\ 0 &amp; \cdots &amp; \cdots &amp; \cdots &amp; \cdots &amp; c &amp; a \end{pmatrix}$$      Here $a,b,c$ can be taken to be real numbers, or complex numbers.   In other words, the matrix $M_n(a,b,c) = (m_{ij})_{1 \le i,j \le n}$ is such that $$m_{ij} = \begin{cases} a &amp; i = j, \\ b &amp; i = j - 1, \\ c &amp; i = j + 1, \\ 0 &amp; \text{otherwise.} \end{cases}$$  There does not seem to be an easy pattern to use induction: the matrix is not a diagonal  of the type $M = \bigl(\begin{smallmatrix} A &amp; C \\ 0 &amp; B \end{smallmatrix}\bigr)$ (where we could use $\det(M) = \det(A) \det(B)$ for the induction step), and there are no lines or columns with only one nonzero entry, so  gets complicated quickly.  Is there a general pattern that one could use? Or is the answer only known on a case-by-case basis? It's possible to compute the determinant by hand for small $n$:  $$\begin{align} \det(M_1(a,b,c)) &amp; = \begin{vmatrix} a \end{vmatrix} = a  \\ \det(M_2(a,b,c)) &amp; = \begin{vmatrix} a &amp; b \\ c &amp; a \end{vmatrix} = a^2 - bc \\ \det(M_3(a,b,c)) &amp; = \begin{vmatrix} a &amp; b &amp; 0 \\ c &amp; a &amp; b \\ 0 &amp; c &amp; a \end{vmatrix} = a^3 - 2abc \end{align}$$  But there is no readily apparent pattern and the computation becomes very difficult when $n$ gets large. Proving that if $ad-bc = \pm 1$, then $\gcd(x,y) = \gcd(ax +by, cx + dy)$ I'm having issues figuring out how to approach this problem:     Conclude that if $ad-bc = \pm 1$, then   $$\gcd(x,y) = \gcd(ax +by, cx + dy)$$   The fact that $\gcd(x,y) = \gcd(x+ky, y)$ is a very special case of this exercise   I believe there is a property that if $a = bq_1 + 0$ where 0 is r, then b divides a, and $b=\gcd(a,b)$  Is that at all relevant in this case? How can orbitals be oriented if the nucleus is symmetrical? I know very little about quantum physics, but I just can't wrap my head around the fact that non-spherical orbitals appear to be "oriented", constituting a set of fixed "frame of reference axes".  Does it really work like that? Are there for a single atom given directions in which the orbitals "protrude"? And if so, what are they based on? If I understand it right, the nucleus is seemingly spherical - symmetrical with no unique axis of symmetry. What would then decide the orientation of the orbitals in space (with respect to the surroundings)?  Edit: I understand any orientation works to satisfy the wave equation. I was more curious why the atom would choose one direction, instead of any of the others. Is that fundamentally random? And is this setup retained further, or can it change at any time? How do I get Gmail to ask me to be a mailto handler again? According to      there         adverb          in or at that place (opposed to here ):      She is there now.         pronoun          (used to introduce a sentence or clause in which the verb comes before its subject or has no complement):      There is no hope.   Then, what element is there in:     There is the man.   I'm confused because "There is the man" is an adverb inversion, in which there is an adverb and "the man is" is inverted. But according to the definition above, there suddenly becomes a pronoun. I'm very confused about tenses.  I have examples in two different situations here. Situation 1: I went to New York two months ago and was talking to someone about it.  A. This is the first time I've been to New York. B. That was the first time I'd been to New York.  Which is correct in a daily conversation?  Situation 2: I'm going to New York next month and talking to someone.  A. This will be the first time I've been to New York. B. This is the first time I've been to New York. C. This will be the first time I go to New York.  Which sentence is appropriate?  According to a grammar article I've read before, I think it says that I can use this sentence in both cases:  This is the first time I've been to New York.  But I'm not sure if this is really so. So I'd like to know which tense I should use in each case. Could you explain it? How to install Flash player on Ubuntu? Disallow downvoting other answers if I've posted my own Possible Duplicates:        As Dan Dyer mentioned in his comment on , there is a conflict of interest when you have posted your own answer and are allowed to downvote other answers.  Despite the vote editing window being drastically reduced, the fundamental problem remains: I can downvote the other answers permanently and still benefit - my answer gets upvoted ONCE and wham, I have just made up the rep loss for my 10 other downvotes. The vote editing window fixes part of the problem, but there is a more complete fix that has the extra benefit of not preventing legitimate vote changes: to disallow downvotes on competing answers when you have posted one yourself.  The temptation to wrongfully downvote competing answers is huge. The rep loss is tiny in comparison. It has to be in order for people to continue to legitimately downvote.  Details:   If I have previously voted and then post my own answers, delete my downvotes. Continue to allow me to remove the upvotes - I think this is fully legitimate. If I delete my answer it's probably best to continue to deny downvotes (perhaps even including the question), but I don't have a strong opinion either way. Does anyone know of a program or way to log all network activity to a specific program on one's computer (program and/or service)?  I know I can see this "live" in Resource Monitor, but I'm wondering if anyone knows of a program or way to track and log all network activity to/from a specific process and/or service.  I'm finding a lot of "live"-type monitors, like Windows Resource Monitor, but nothing that can log. What is the difference between SAN, NAS and DAS? What is the difference between SAN, NAS and DAS? How to migrate from test environment to production environment? The migration is from the local environment to the production environment. The production environment has run some time and created a lot of articles.   In order to add new things to my site, I added a custom theme and installed CCK, Views and other modules in my local test environment. Now that the local test environment is finished, how do I migrate it to the production environment, without destroying the content of its database? Uninstall Kali Linux from triple boot Attempt to de-reference a null object: Trigger There were custom validation error(s) encountered while saving the affected record(s). The first validation error encountered was:      Apex trigger updatequotestatus caused an unexpected exception, contact your administrator: updatequotestatus: execution of AfterInsert caused by: System.NullPointerException: Attempt to de-reference a null object: Trigger.updatequotestatus line 5, column 1.   Error Occured at Line:     if((t.what.getsobjecttype() == quote__c.sobjecttype) &amp;&amp; (t.subject.substring(0,5) == 'Email')  trigger updatequotestatus on task (after insert, after update){     Set&lt;Id&gt; quoteIds = new Set&lt;Id&gt;();     List&lt;quote__c&gt; quotes = new List&lt;quote__c&gt;();      for(task t:trigger.new){         if(t.whatId!=null){             if((t.what.getsobjecttype() == quote__c.sobjecttype) &amp;&amp; (t.subject.substring(0,5) == 'Email')){                 quoteIds.add(t.whatId);             }         }     }      for(quote__c q:[select StageName__c from quote__c where Id IN : quoteIds]){         quote__c qt = new quote__c();         qt.Id = q.Id;         qt.StageName__c = 'Proposal Sent';         quotes.add(qt);     }      if(quotes.size()&gt;0){         update quotes;     } }