output stream in C++ If I have opened an output stream like this:     ofstream to(output_file);  How may I print new line (Looking to support different os)?  to &lt;&lt; &quot;\n&quot;;  to &lt;&lt; &quot;&quot; &lt;&lt;endl;
"std::endl" vs "\n" Many C++ books contain example code like this...  std::cout &lt;&lt; "Test line" &lt;&lt; std::endl;   ...so I've always done that too. But I've seen a lot of code from working developers like this instead:  std::cout &lt;&lt; "Test line\n";   Is there a technical reason to prefer one over the other, or is it just a matter of coding style?
XIV pages in page counts? Is there a formula for $(1+i)^n+(1-i)^n$? I'm wondering if there is a formula for the value of $(1+i)^n+(1-i)^n$?  I calculated the first terms starting with $n=1$ to be, in order, $2$, $0$, $-4$, $-8$, $-8$, $0$, $16$, $\dots$  So it seems to be some sequence of positive and negative powers of $2$ with $0$s thrown in. Is there a more explicit formulation of what $(1+i)^n+(1-i)^n$ is, based on $n$?   With the binomial theorem, I get it equal to $$ \sum_{k=0}^n\binom{n}{k}i^{n-k}(1+(-1)^{n-k}). $$ Can this be made nicer? Thanks. Using 'for' as a coordinating conjunction at the beginning of a sentence – is this acceptable? As I understand it, 'for' is a coordinating conjunction. Learning German as a second language has taught me specifics about reforming sentences, but it is an awful lot less common in English. If I were to rearrange the sentence: "I ate lunch, for I was hungry," so that 'for' was the first word of the sentence, by my reckoning I should end up with "For that I was hungry, I ate lunch." Does this new sentence have any grammatical errors? I inserted the word 'that' after 'for', because without it the sentence didn't sound right. Should I have? Is there a rule for that? Thank you in advance, an aspiring author.  Additional Information:  I am not having problems with the sentence, this is a general question to increase my knowledge of the manipulations of coordinating conjuntions. I am very new to cryptography (so be kind), but I have a question that may seem silly.   If the one-time pad is the perfect cipher and impossible to crack, why would the following algorithm not be one of the strongest:  To encrypt:   generate a random bit array using a pseudo number generator with the key as the seed  The generated bit array is the size of the data use a simple XOR to encrypt using the generated bit array   To decrypt:   pseudo-random number generator will generate the same bit array with the same seed (the key) generate bit array the same size of the encrypted data run XOR on encrypted data using bit array that's generated   This is very simplified, but you can imagine how for larger encryption you could break down the data into blocks, and in order to ensure that the block bit arrays are random a new seed for each can be derived from the key. So, if $f(k)$ is the pseudo random number generator, and b is the block number, you can encrypt each block with $f(k+b)$. ($k$ is key)   Instead of using a pseudo-random number generator, you could use some hash algorithm to generate the pad.    (assuming you can use equivalently strong keys) would this not be a very strong cipher method? Perhaps it may be strong and heavy on memory since the pad needs to be the size of the data. So during encryption and decryption you need to generate a pad that's equivalent to the size of the data.   Is there a flaw in this algorithm, or would something like this not be practical and much slower than current standards? I have the following code  &lt;?php if ($handle = opendir('C:/xampp/htdocs/movies')) {     while (false !== ($file = readdir($handle))) {         if ($file != "." &amp;&amp; $file != "..") {             echo $file."&lt;br /&gt;\n";         }     }     closedir($handle); } ?&gt;   When it does have mb language such as japanese, it doesn't display properly instead it display like kyuukyoku Choujin R ?????~? rather then kyuukyoku Choujin R 究極超人あ～る  Anyway to make it display the correct name or make it still download-able by others?  Thanks for helping me :) Google Sheets has several import functions   IMPORTDATA IMPORTFEED IMPORTHTML IMPORTXML   Sometimes the above functions returns errors like #N/A Imported content is empty and would like to be sure that there isn't a problem with the resource content to be imported.  How do I know if these functions are able to get the content that I looking to import?  I know that there also exist IMPORTRANGE but that function only is able to import content from Google Sheets spreadsheets Can a mathematically sound prediction interval have a negative lower bound? I have used R to form a 95% prediction interval for the number of endemic species on an island. My lower bound is negative – is that mathematically sound?  In the linear model used in the prediction interval, the data used are:  Area Surface area of island, hectares DiscSC Distance from Santa Cruz, kilometres Elevation Elevation of higher point in metres and it is coded as such:   selected.model &lt;- lm(ES ~ Area + Elevation + DistSC + I(Elevation^2)                      + (Elevation:DistSC) + (A‌​rea:Elevation))    and stepwise regression was performed to find this "best" model   I'm not exactly sure how a prediction interval works. I just want to make sure it is OK. Obviously a negative number of species is incorrect, but I know it takes into account the uncertainty of the mean as well as data scatter. How To Set Default Wallpaper As Login Screen Wallpaper [Automatically]? WMI object to get current sessions with client name? Emulate "double" using 2 "float"s What I want to achieve is very simple: I have a Windows Forms (.NET 3.5) application that uses a path for reading information. This path can be modified by the user, by using the options form I provide.  Now, I want to save the path value to a file for later use. This would be one of the many settings saved to this file. This file would sit directly in the application folder.  I understand three options are available:   ConfigurationSettings file (appname.exe.config) Registry Custom XML file   I read that the .NET configuration file is not foreseen for saving values back to it. As for the registry, I would like to get as far away from it as possible.  Does this mean that I should use a custom XML file to save configuration settings?  If so, I would like to see code example of that (C#).  I have seen other discussions on this subject, but it is still not clear to me. I recently read the .  This book had the idea of the time you live as something that can be used to pay for things. When you run out of "money" you die.  I was wondering is this the original source for this idea? Or does anyone know of an earlier book with the same idea? How to build a custom kernel? How to make a through hole using inward extrusion in Blender 2.8? I am trying to make a through hole using inward extrusion. I enterd into edit mode, then I drawed an outline of my hole using knife tool. then I turn into wireframe shading, rotate my view an select snap to faces and then extrude the hole outline inward  so the hole is created successfully, but I still have a face at the hole bottom. I can select this face separately  But If I try to delete it, I siply delete this face (I can't select it anymore after deleteting), but I do not see through hole, so the basic cube face is still here. So how to remove the hole bottom? Regular Expressions: Is there an AND operator? Obviously, you can use the | (pipe?) to represent OR, but is there a way to represent AND as well?  Specifically, I'd like to match paragraphs of text that contain ALL of a certain phrase, but in no particular order. Machine learning cookbook / reference card / cheatsheet? I find resources like the  and  incredibly useful. They obviously serve well as references but also help me to organize my thoughts on a subject and get the lay of the land.   Q: Does anything like these resources exist for machine learning methods?  I'm imagining a reference card which for each ML method would include:   General properties When the method works well When the method does poorly From which or to which other methods the method generalizes. Has it been mostly superseded? Seminal papers on the method Open problems associated with the method Computational intensity   All these things can be found with some minimal digging through textbooks I'm sure. It would just be really convenient to have them on a few pages. Let $n \geq 1$ be an odd integer. Show that $D_{2n}\cong \mathbb{Z}_2 \times D_n$. Let $n \geq 1$ be an odd integer. Show that $D_{2n}\cong \mathbb{Z}_2 \times D_n$. I define a map $$\phi:D_{2n} \rightarrow \mathbb{Z}_2 \times D_n$$ by $R \mapsto (0,r^{\frac{n+1}{2}})$ and $M \mapsto(1,m)$. Then I am stuck at showing the map is bijective. By the way, do we need to show that $(0,r^{\frac{n+1}{2}})(1,m)(0,r^{\frac{n+1}{2}})^{-1}=(1,m)$ ? If we can prove this, then what can we conclude? How do you run a Python script as a service in Windows? How does passive perception work Total noob question, but the passive perception is confusing. I don't understand how to calculate it or use it, and I need help. How do I connect to a MySQL database using a python program?