I try to multiply an integer by a double but I obtain a wrong result. In my example the result of v * decimals is 11.9999999999... instead of 12 although when I print it using cout it shows 12 (I see the value using gdb), then static_cast set 11 in uint64_t a. Why does this happen? What is the correct way to multiply an integer and a double?   #include &lt;iostream&gt;  int main(int argc, char *argv[]) {     const uint64_t decimals = 100000000;     double v = 0.00000012;     uint64_t a = 0;      std::cout &lt;&lt; "Initial value=" &lt;&lt; v &lt;&lt; std::endl;     v = v * decimals;     std::cout &lt;&lt; "v * decimals=" &lt;&lt; v &lt;&lt; std::endl;     a = static_cast&lt;uint64_t&gt;(v);     std::cout &lt;&lt; "a=" &lt;&lt; a &lt;&lt; std::endl;      return 0; }   output:  Initial value=1.2e-07 v * decimals=12 a=11
Consider the following code:   0.1 + 0.2 == 0.3  -&gt;  false   0.1 + 0.2         -&gt;  0.30000000000000004   Why do these inaccuracies happen?
Make a div fill the height of the remaining screen space I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ } &lt;table id="page"&gt;     &lt;tr&gt;         &lt;td id="tdheader"&gt;             &lt;div id="header"&gt;...&lt;/div&gt;         &lt;/td&gt;     &lt;/tr&gt;     &lt;tr&gt;         &lt;td id="tdcontent"&gt;             &lt;div id="content"&gt;...&lt;/div&gt;         &lt;/td&gt;     &lt;/tr&gt; &lt;/table&gt;     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works. Discontinuous functions with closed graphs I tried looking up a question regarding graphs of continuous functions on this site, but all the ones I found consider functions from $\mathbb{R}$ into $\mathbb{R}$. I have been pondering the following question: given a general topological spaces $X, Y$, and a function $f: X\to Y$, when does $Graph(f)$ closed in $X\times Y$ imply that $f$ is continuous. By the closed graph theorem, this is true whenever $X$ and $Y$ are both Banach spaces.   Also, it is fairly easy to prove that whenever $Y$ is a Hausdorff space and $f$ is continuous, then $Graph(f)$ is closed, but I do not think that the converse is true, so I am trying to find an example where $X$ is some topological space, $Y$ a Hausdorff space, $f: X\to Y$ a function with a closed graph in $X\times Y$, but who fails to be continuous. As of yet I have not been able to find such a counterexample, partially because I have no clue where to look for such a counterexample. I would really appreciate getting some directions to go in. Changing Vim indentation behavior by file type Could someone explain to me in simple terms the easiest way to change the indentation behavior of Vim based on the file type? For instance, if I open a Python file it should indent with 2 spaces, but if I open a Powershell script it should use 4 spaces. number of trailing zeros Prove by induction that $n! > 2^n$ Suppose that when $n=k$  $(k\geq4)$, we have that $k!&gt;2^k$.  Now, we have to prove that $(k+1)!\geq2^{k+1}$ when $n=(k+1)$ $(k\geq4)$.  $$(k+1)! = (k+1)k! &gt; (k+1)2^k  \text{ (since }k!&gt;2^k)$$  That implies $(k+1)!&gt;2^k2$, since $(k+1)&gt;2$ because of $k$ is greater than or equal to 4.  Therefore $(k+1)!&gt;2^{k+1}$  Finally  we may conclude that $n!&gt;2^n$ for all integers $n\geq4$    Solved, thank you! Extract single file from tar to other folder I've searched for multiple forums for this questions and have seen different answers but so far, nothing have worked yet even from the ones I've seen here.  I want to extract a single file from a tar to a different directory.  I've tried this:  tar xvf file.tar -C /home/dir/ filename   or this:  tar -x filename -f file.tar -C /home/dir   But got these errors respectively:  x filename, 14826 bytes, 29 media blocks. File -C not present in the archive. File /home/dir not present in the archive.   and:  tar: /dev/rmt0: A file or directory in the path name does not exist.   The first extracted the file but in the same directory, not to the folder I wanted. Explaining to laypeople why bootstrapping works Asking the user for input until they give a valid response Changing my iTunes account details Color Transfer from colored image into grayscale image How to find a program which is preventing sleeping? I am noticing that recently my laptop does not go to sleep/lockout after its configured X minutes of inactivity like it did in the past. I suspect some program (like media player does) is preventing it from going to sleep. I do not have any media player running, so how can I find which program is preventing it from sleeping?  It does go to sleep if I close the lid. But I would also like for it to go to sleep after X minutes of inactivity.  Update: Upgraded to Ubuntu 18.04 with default Gnome and Wayland enabled. So my friend has a USB flash drive that isn't working. I don't know a whole lot about "recovery" software so I figured I'd ask you guys.  What steps can I try (I have access to a Linux machine as well) to see....if I can get ANYTHING off the flash drive?  I've google'd around, but most of the stuff seems for windows. What is Elrond's position/status, as compared to Galadriel's? In the Lord of the Rings books, Galadriel of Lorien is even more exalted than in the movies.  She is essentially a queen, and the deference shown to her far exceeds that shown to Elrond of Rivendell.  Yet in the films, we see her trying to persuade Elrond to intervene in the battle of Helm's Deep by sending Elf troops to reinforce Theoden's forces.  Eventually, Elrond relents, and orders the Elves into battle.  But the troops in question are Galadriel's, not Elrond's - they are led by Haldir, one of Galadriel's guards; the trip from Rivendell to Helm's Deep (500 miles as the crow flies) is about 2 times longer than the trip from Lorien to Helm's Deep (250 miles as the crow flies), far too long for the reinforcements to arrive in time.  But then Haldir greets Theoden of Rohan by saying he has come bearing a message from Elrond - not Galadriel.     I bring word from Lord Elrond of Rivendell. An Alliance once existed between Elves and Men. Long ago we fought and died together. We come to honor that allegiance.    This seems odd for a few reasons. The troops are Galadriel's, not Elrond's, and they come from Lorien, not Rivendell. She clearly wanted to send them to Helm's Deep - she was cajoling, prodding, and guilt-tripping him into doing just that.  She is also a queen, and could presumably order them into battle regardless of what Elrond says.    So why does she have to talk Elrond into letting her send her own troops into battle, especially when he is too far away to contribute manpower (elfpower) or materiel to the battle of Helm's Deep?  Why not say, "I'm not going to sit here doing nothing while Saruman runs roughshod over Rohan;  you can support me or not, Elrond, but if you aren't willing to help, you can at least get the hell out of the way"?  Why does her aide Haldir "bring word from Elrond" when the troops - and the impetus for sending them - came from Galadriel, and Elrond resisted sending them out for as long as he could?  And again, what is Elrond's official position/status/rank, and why would a queen need his permission to deploy her own troops? If I want to draw an overline over some text, not an equation, how can I do it? \overline seems to only work in math mode, and when used outside of math mode, it automatically says "Missing $ inserted". In Catan, can you continue a "circular" road? If I have 6 roads that go all around a single hex tile, they are a continuous uninterrupted road (assuming none of my opponents interrupts it with their settlements/cities). But, can I continue this 6-piece road and create a 7-piece continuous road by building a road that goes out of this hex tile? Here's an image of what I'm talking about:    Is this a valid 7-piece continuous road? Ubuntu 18.04 hangs on booting with message "started user manager for uid 120" on Asus 1015PX I installed Ubuntu 18.04 amd64 desktop on Asus Eeepc 1015px, but it hangs on booting. The last message is 'Started User Manager for UID 120'.  I managed to boot up in recovery mode and finished the installation with 'sudo apt-get upgrade', but nothing has changed.  Does anybody know how I can tackle it?  Thanks in advance, Newton. How can I restart an app game from the beginning What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally? I want to find the conjugacy classes of this group: $$G=\{(a_1,a_2,a_3):a_i=\pm e_j\}\subset GL_3(\mathbb C)$$ I know that $S_3$ is one of the subgroups of this group, so I can check which elements of $S_3$ continues to be conjugate in our group, I know that in $Z(G)$ there is two elements $I,-I$. I know that I have to check the diagonal matrices on which ones are conjugate, but I don't know how to finish and find the others conjugacy class of this group, and I don't Know how to find the number of the elements of the conjugacy class. I'll be thankful for help "Is there" versus "Are there" Are there any questions I should be asking?   Is there any articles available on the subject?   My instinct is that in the two questions above, it should be 'are' as the subjects of the sentences (questions/articles) are plural.  However I also recall being told that the singular 'is' is valid here too, and of course see it very often in usage online, and this has left me a bit unsure.  Update: I have stumbled upon the reason for the confusion.     Is there any water?   Are there any questions?   The sentence structure is the same but of course water is not plural, although it is not singular either.