In this code:  Console.WriteLine(&quot;Hello {0}&quot;, name);  How is this {0} called? I'm starting in C# and I've seen some codes with this. I kind of know how it works, but why should I use (&quot;Hello {0}&quot;, name) instead of (&quot;Hello &quot; + name)?
In a dictionary like this:  Dictionary&lt;string, string&gt; openWith = new Dictionary&lt;string, string&gt;();  openWith.Add("txt", "notepad.exe"); openWith.Add("bmp", "paint.exe"); openWith.Add("dib", "paint.exe"); openWith.Add("rtf", "wordpad.exe");  Console.WriteLine("For key = \"rtf\", value = {0}.", openWith["rtf"]);   The output is:     For Key = "rtf" value = wordpad.exe   What does the {0} mean?
I want to enable GPU rendering, but there is no option in User Preferences > System:    Why is this? How can I get cycles to render using my GPU? Probability that all three shirts were worn Mr. Jones has three shirts: Red, Green and White. Each day he picks randomly a red shirt with probability of $\frac{1}{2}$, green with probability of $\frac{1}{3}$ and white with probability of $\frac{1}{6}$.     What is the probability that he wears all three shirts after 6 days?   My try:   $$\binom{6}{1}\binom{5}{1}\binom{4}{1}\frac{1}{2}\cdot\frac{1}{3}\cdot\frac{1}{6}\cdot[\binom{3}{2}(\frac{1}{2})^2\cdot[\frac{1}{3}+\frac{1}{6}]+[\binom{3}{2}(\frac{1}{3})^2\cdot[\frac{1}{2}+\frac{1}{6}]+[\binom{3}{2}(\frac{1}{6})^2\cdot[\frac{1}{2}+\frac{1}{3}]+\binom{3}{1}\binom{2}{1}\frac{1}{2}\cdot\frac{1}{3}\cdot\frac{1}{6}]$$  First, we pick possessions for red, green and white. Then, we multiply it by the other combinations possible of the other three possessions left, and summing it up (I didn't count all possibilities). The problem is the answer is bigger than 1, so it must be wrong. Also, I guess there is more elegant way.  Thanks in advance. Determine the size of a C++ array programmatically? This question was inspired by a similar question:   My question is a little different:  Is there any way to determine the size of a C++ array programmatically?  And if not, why?  Every function I've seen that takes an array also requires an integer parameter to give it the size.  But as the linked question pointed out, delete[] must know the size of the memory to be deallocated.  Consider this C++ code:  int* arr = new int[256]; printf("Size of arr: %d\n", sizeof(arr));   This prints "Size of arr: 4", which is just the size of the pointer.  It would be nice to have some function which prints 256, but I don't think one exists in C++.  (Again, part of the question is why it doesn't exist.)  Clarification: I know that if I declared the array on the stack instead of the heap (i.e. "int arr[256];") that the sizeof operator would return 1024 (array length * sizeof(int)). How to compile a function whose arguments are lists containing strings? Etymology of "cut someone some slack" Teenagers. All the literature tells you one thing and one thing only – that  whatever they are doing, give them a break, cut them some slack, it's normal.      From the novel, Apple Tree Yard   I'm curious about the origins of . I know slacks are American English for trousers or pants, and a slacker is a lazy person. But what is a slack and how does one "cut" it? Will metering from a DSLR apply to a film SLR? I still like to shoot with film (I use a Nikon F3) but I like the immediate feedback of digital.  I'm thinking of buying a used DSLR to help me get the framing and lighting right when I shoot static subjects.  Then I'd take the final shot with my F3. But would the metering be transferable?  If the shot looks perfect at 1/125 with f/2 on a DSLR, will the same settings work on a film camera? I have noticed a couple of kinds of behavior that seem to crop up in the SO community, and it really seems to artificially boost reputation. There may not be a solution (or it may not be a problem!) but here are some thoughts.  The first is the fact that "celebrity" users, or users with lots of reputation, are treated significantly better than others. Take Joel Spolsky's most recent question:    It was closed, opened, closed, and re-opened. And the question has earned Joel - what - 1030 reputation 103 votes, and lots of reputation! Wow! I'm not saying that Joel's question is a bad one. But lets compare to other questions that one might consider to be in the same equivalence class - easily answerable, specific questions, short questions:   (5 votes)   (5 votes)  If you look at the , I can hardly find any which are specific technical questions. So that Joel's question was so upvoted could only mean that:   It was upvoted based on his celebrity People have been interpreting the questions as a sort of zen-like wakeup call, designed to get people talking and thinking about they way they vote.   I do not mean any disrespect toward Joel, and again, I think his question was a good one. This post isn't about Joel! But the boost in reputation did not (imho) mean "Joel is really good at programming, and he has earned my trust as someone knowledgeable about computers." It may be true that Joel is a proficient computer expert, but not based on the merit of that one question.  Which leads me to an example about myself. I recently gave  (130 reputation) to a question about PHP's image-creating libraries. I am very appreciative of the community's support for my answer - an answer which I believe was well-thought and that I put effort into.  At the same time I can't look someone and tell them, with a straight face, that my reputation is a great reflection of my computer-related knowledge. Billions of people on the net have created tutorials for PHP's GD image library - I just happened to be the person to post a few of them. Heck if I know why it got 13 votes! (oh, but please don't downvote it!!)  SO is built by the community - so the community absolutely gets to decide what questions are important, and how they choose to dispense reputation. But in practice, I feel like peoples' reputation would be much lower if the community were more discriminating about the way they voted.  So: am I totally off base here? Is this even something that can be corrected with a different reputation algorithm? Or am I the only one who sees this as a detriment to the SO community?  (And, to be completely clear, I do not intend for this to be an ad hominem, and I am not jealous about not having a higher reputation. But I do take reputation with a grain of salt, in part for these reasons, and I thought I'd bring it up! It is meta, after all!) Missing SOAP action header Im trying to get the session ID of another user in the same org by sending the following request by using the data from my enterprise wsdl and its an developer edition.  &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:enterprise.soap.sforce.com"&gt;    &lt;soapenv:Header&gt;       &lt;urn:organizationId&gt;xxxxxxx&lt;/urn:organizationId&gt;    &lt;/soapenv:Header&gt;    &lt;soapenv:Body&gt;       &lt;urn:login&gt;          &lt;urn:username&gt;xxxxxxxxx&lt;/urn:username&gt;          &lt;urn:password&gt;xxxxxxxxx&lt;/urn:password&gt;       &lt;/urn:login&gt;    &lt;/soapenv:Body&gt; &lt;/soapenv:Envelope&gt;   But when i send this request i get      Missing SOAP ACTION header  but in my wsdl i dont have the action ,its blank    how to overcome this problem ?I got totaly struck over here since there is no action though its asking for action header.Following method handles the http request.   public string   processrrequest(string ep,string message,string method) {      HttpRequest req = new HttpRequest();     req.setEndpoint(ep);     req.setMethod(method);     req.setHeader('Content-Type', 'text/xml');     req.setHeader('SOAPAction','');     req.setBody(message);     system.debug('Request::'+req.getbody());     Http http = new Http();     HttpResponse res =http.send(req);     //Dom.Document doc  = res.getbodyDocument();     system.debug('Response::'+res.getbody());     system.debug('Response2::'+res.getStatus());     Dom.Document doc= new Dom.Document();     doc=res.getBodyDocument();     system.debug('doc::'+doc);     return 'hai'; } $a,b,m,n$ be positive integers such that g.c.d.$(a,b)=1$ and $a^m+b^m|a^n+b^n$ , then $m|n$? Let $a,b,m,n$ be positive integers such that g.c.d.$(a,b)=1$ and $a^m+b^m|a^n+b^n$ , then is it true that $m$ divides $n$ ? Is there a problem with closing the lid of a MacBook Pro when using an external monitor? I am using an external monitor and the only way (that doesn't involve jumping through hoops) to turn off the MacBook Pro monitor is to close the lid.  Does closing the lid causes any problems? I have read the following on :     You can still run a single external monitor if you close the lid of   your laptop, but that restricts airflow and exposes your display to a   lot of heat. Not good. I'm looking for the title of an anthology of children's science fiction stories from the 1950s. The best of the bunch involved a Martian who visited earth, and realized we'd blown ourselves up in a nuclear war and had fallen into savagery. The Martian is a vegetarian who subsists on biscuits made by a machine he brought with him, and communicates by using one of his tentacles to feed messages direction to/from the brain of the person he's talking to.  Inadvertently left behind by his expedition, he initially befriended some children, and eventually managed to rebuild civilization. Presently he dies, but when another expedition comes a generation later, they find the civilization he rebuilt.  there were other stories, but that was the best one.   If I can't find the name of the book it was in, I'd be happy to settle for the name of the author and the title of the story. While I am familiar with Descartes and the oft-quoted idea, I think therefore I am, I am not familiar with any philosophy that actively sought to rationalize that anybody else exists.  Are there philosophers who analyzed this question? Or is it taken for granted that it is (im)possible for anybody to validate their own existence to somebody else? Stanley's Enumerative Combinatorics () contains next fact: 1.1.3 Example. Let f(n) be the number of n × n matrices M of $0$’s and $1$’s such that every row and column of M has three 1’s. For example, f(0) = 1, f(1) = f(2) = 0, f(3) = 1. The most explicit formula known at present for f(n) is $$f(n)=6^{-n}{(n!)}^2\sum\frac{(-1)^{\beta}(\beta+3\gamma)!2^\alpha 3^{\beta}}{\alpha!\beta!\gamma!^26^{\gamma}}$$ where the sum ranges over all (n + 2)(n + 1)/2 solutions to α + β + γ = n in nonnegative integers.   I need proof of this fact. (i.e. reference to book or articles that contains proof this fact). Prove that the ideal $(X_1-a_1,...,X_n-a_n)$ is maximal in $K[X_1,\dots,X_n]$ Let $K$ be a field, and $a_1,\dots,a_n \in K$. Prove that the ideal $$(X_1-a_1,\dots,X_n-a_n)$$ is maximal in $K[X_1,\dots,X_n]$.   I tried proving that the only elements outside the ideal are the invertibles of $K$ (I should still prove that this implies maximality, but it shouldn't be too difficult).  Is there a better strategy, or another stategy? On the one hand, I'm aware that  in the US do not have a valid government ID. On the other hand, traveling within the US requires you to show a piece of ID wherever you go - even when taking a Greyhound.   So let's say you're an American who has a large number of cash in their pocket but no ID whatsoever. Would you be able to get from New York to San Francisco or from Seattle to Miami? If so, what are your options? Even though I do have plenty of identification documents, I find it enjoyable to be able to travel anonymously. Accidentally deleted /etc/fstab file I accidentally deleted my /etc/fstab file by running sudo rm /etc/fstab. Without realising what I'd done, I shut down my Ubuntu OS.  Now I'm not able to boot.    My screen looks like this. In some cases, a purple screen appears. Please give me some solutions. What are the scope restrictions for setting shopt extglob. and other options? My non-interactive bash shell has extglob off. I would like to turn it on in the statement immediately before a command, but I have noticed that when shopt -s extglob is within an if .. then .. else block, it somehow does not register.   The following extglob-dependant command is not valid: syntax error near unexpected token '('.     Where can extglob be set, and why is there a restriction, at all? Does this apply to other options?  ... GNU bash 4.1.5     This works:    shopt -s extglob if true ;then     touch a.bcd; ls a.@(bcd) fi   This fails:    if true ;then     shopt -s extglob     touch a.bcd; ls a.@(bcd) fi ... line 17: syntax error near unexpected token `(' ... line 17: `touch a.bcd; ls a.@(bcd)' If perimeter of a triangle is $2d$, what is the length of sides so the triangle has maximal area?    I found some solution using circle and angles, but I think I have to use derivatives.    I need help. Elastic net penalty Let's say that you want to output or concat strings. Which of the following styles do you prefer?   var p = new { FirstName = "Bill", LastName = "Gates" }; Console.WriteLine("{0} {1}", p.FirstName, p.LastName); Console.WriteLine(p.FirstName + " " + p.LastName);   Do you rather use format or do you simply concat strings? What is your favorite? Is one of these hurting your eyes?  Do you have any rational arguments to use one and not the other?  I'd go for the second one.