sizeof(array) in C: segmentation fault
Getting a stack overflow exception when declaring a large array
How should I implement hook_menu()? Good books for a high schooler self-studying Abstract Algebra? Does anyone have any suggestions for abstract algebra books particularly suited to self-study?     Here is some background and motivation, if it's helpful.  I'm currently a junior in high school, but I have some familiarity with groups, rings, polynomials and fields, as I went through Fraleigh's book. I liked its writing style, but many of the problems were not helpful. I would like to get better at algebra with some other book, particularly one that's aimed at someone who already has a little familiarity with the objects, but is by no means completely comfortable.  One of my longer-term goals is to learn a bit of algebraic number theory, as I've only been studying elementary number theory. That's why I feel it  good to learn more algebra first. (I'd also be interested in suggestions of other good subjects to learn prior to tackling algebraic number theory.)  I was considering using one of Lang's books, since they seem pretty universal, but I've heard rumors that they are very terse and not good for self-learning. Is it a scam if the person only wants to deposit into my account, not make a withdrawal? A man in  west  coast  Austria wants to deposit money  into  my account.  I'm in Alabama.  I had to get an online  account.  I did that, but he says his bank manager  needs all this information:   DOB SSN    online access username  online access  password   security  question and answer   bank name   bank address   bank number  person who is on the account     their name their address    account no   routing no     OK. Is it safe  to do this or am I being scammed?  I don't want him  to be able to end up withdrawing all my money instead of depositing money. Can somebody help me with the execute commands in Minecraft? Recently, Minecraft had removed the /testfor command, which broke these sets of commands that I was trying to execute today.  /testfor @p[r=10] {SelectedItem:{id:"minecraft:feather",tag:{display:{Name:"Roc's Feather",Lore:[Jump higher using this feather.]}}}}`   Now normally, from Minecraft 1.13 onwards, the new /execute command would've been the replacement for the /testfor command, but as I soon found out, the command failed to detect my Roc's Feather and thus could not execute an /effect command that gave me a Jump Boost, for 1 second, at level 3.  I tried remaking my feather from scratch with this command here:  /give @p minecraft:feather{display:{Name:"{\"text\":\"Roc's Feather\",\"color\":\"light_purple\",\"bold\":true,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}",Lore:["{\"text\":\"Jump higher using this feather.\",\"bold\":false,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}"]}} 1   But the execute command I placed did not detect this type of uniqueness.  /execute if entity @p[distance=10,nbt={SelectedItem:{id:"minecraft:feather",Count:1b,tag:{display:{Name:"{\"text\":\"Roc's Feather\",\"color\":\"light_purple\",\"bold\":true,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}",Lore:["{\"text\":\"Jump higher using this feather.\",\"bold\":false,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}"]}}}}] run effect give @s minecraft:jump_boost 1 3 true   Can somebody tell me what I'm doing wrong here because I cannot even tell what's the issue. I'm using Ubuntu 13.04 and I have ASUS X550V laptop. This is my rfkill list:  0: asus-wlan: Wireless LAN     Soft blocked: no     Hard blocked: no 1: asus-bluetooth: Bluetooth     Soft blocked: no     Hard blocked: no 2: phy0: Wireless LAN     Soft blocked: no     Hard blocked: yes 3: hci0: Bluetooth     Soft blocked: no     Hard blocked: no   Before you start going: Hey, just turn on your hardware switch, dummy... my hardware switch is Fn + F2 and it works perfectly fine on my Windows boot. But, on my Ubuntu boot it does nothing... All the other Fn + F_ combos work (turn off the touchpad, screen turn off, screen brightness, sound) and they give some kind of visual indicator when I press it.  My lshw log:  *-network DISABLED                 description: Wireless interface                 product: AR9485 Wireless Network Adapter                 vendor: Atheros Communications Inc.                 physical id: 0                 bus info: pci@0000:03:00.0                 logical name: wlan0                 version: 01                 serial: 24:0a:64:28:b4:25                 width: 64 bits                 clock: 33MHz                 capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless                 configuration: broadcast=yes driver=ath9k driverversion=3.8.0-19-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn                 resources: irq:17 memory:f7900000-f797ffff memory:f7980000-f798ffff I have a bit of a unique problem. Well, maybe not a problem because I'm really just curious about it, but...  I have a simple 8 digit calculator. It has +, -, x, /, and a constant operation function. It has no usable memory slot.  I need (lit. would like to know how) to calculate ln(x) on this calculator. Any series I have found lose a lot of precision since whatever is outside the 8 digit range is truncated without rounding. I have used Padé approximants with trig functions, and a continued fraction for exp(), but none of these two methods are adequate for ln(x), either because there is no way around the truncation error or it requires writing down many intermediate values, or it requires memorizing and punching in many constants.  Does anyone know any good way to calculate ln(x) (or any other base, since memorizing one constant is OK) to as many digits as possible as easily as possible on this calculator (bonus points to methods where the value on the screen is immediately, meaning you don't need to write it down)?  For that matter, if you happen to know some good ways to calculate other special functions, I am interested in that as well.  Thanks! I see a lot of questions comparing full frame (e.g EF for Canon, FX for Nikon) and crop lenses (e.g. EF-S for Canon, DX for Nikon) but I can't find the answer to what would be the differences between the photos taken with say a 50mm f/1.4 EF and EF-S lenses both used with   same APS-C sensor sized camera same ISO same f/1.4 f-stop same focal length same shutter speed   What would be the resulting differences in the photos? Which one would   be brighter than the other due the EF-S lens concentrating the light more? no that's wrong. Both put the same amount of light from the same FoV on the sensor. have greater depth-of-field? neither less problems towards the edges? generally the full frame more lens flare? generally the full frame lens unless there is, or you provide more shading anything else? not really, unless you start down the road of which one is typically of better build quality.   Edit: Added the answers from what seems to be the general consensus from the multiple answers and comments.  Results: My desire to buy a fast medium-high quality lens compatible with both full frame and crop camera's doesn't have to be hampered by the APS-C sensor size of my current camera.  This means I'm willing to part with more money to get a higher performance/quality lens as the performance/quality will be useful now and when I upgrade my camera.  Though reading reviews of some full frame lenses with short focal lengths, look out, as some are really only made to perform well on crop cameras even though they fit on a full frame camera and will give you a full frame picture, the edge quality is very bad. Earlier today my 2009 iMac emitted I/O errors trying to copy files. So I ran disk utility, verify disk to see if anything was amiss. It was. But as it's my startup disk I couldn't repair it, so I tried safe mode. Safe mode worked the very first time, but when I rebooted it shows the progress bar filling up, before halting. Every time I turn it on now, the same progress bar then crash happens. Booting in verbose mode reveals fsck is failing with signal 8.  Using single-user mode, as that's as far as I'm aware the only way I can get any access to the system, I've been running fsck_hfs. However, it always fails. Below is the output from fsck_hfs -d /dev/disk0s2.  ** /dev/rdisk0s2         Using cacheBlockSize=32K cacheTotalBlock=65536 cacheSize=2097152K. ** Root file system    Executing fsck_hfs (version diskdev_cmds-491.6~3). ** Verifying volume when it is mounted with write access. ** Checking Journaled HFT Plus volume. ** Checking extents overflow file. ** Checking catalog file.    Missing thread record (id = 9931104)    Missing thread record (id = 16434146)    Missing thread record (id = 19370458) disk0s2: I/O error hfs_swap_BTNode: offsets 10 and 11 out of order (0x0000, 0x0000)    Invalid node structure (4, 115897) ** The volume Macintosh HD could not be verified completely.         volume check failed with error 7         volume type is pure HFS+         primary MDB is at block 0 0x00         alternate MDB is at block 0 0x00         primary VHB is at block 2 0x02         alternate VHB is at block 1952491198 0x74622d5e         sector size = 512 0x200         VolumeObject flags = 0x07         total sectors for volume = 1952591200 0x74622d60         total sectors for embedded volume = 0 0x00   I absolutely need to be able to boot to use it as an external monitor. The coupon collectors problem Fastest Gun in the West Problem I feel like there's a problem with Stack Overflow, as the number of people prowling it increases.  Each question's answers are sorted by descending score and then by descending time of posting. This means that if a person sits down and answers a question in a long, thorough way, going through every nook and cranny, once they post their answer, it will already be one of about seven different ones, some of which have already been upvoted. This wouldn't be a problem if those answers were as thorough as the one this guy's posting, but they usually aren't. Some of them are downright wrong, some aren't even answers to the question asked because their poster didn't bother to read the question all the way through.  This causes a problem I like to call Stack Overflow's Fastest Gun in the West Problem. I've come to a point where I'd rather just send a short, simple, correct explanation, than to go and do some proper research, write a whole blog post about it or even make sure the code I post even compiles, just so it will be noticed, as opposed to the incorrect ones.  I'm sure I'm not the only one doing this and that it despairs many people from even trying to answer questions.  I've long ago learned to try to always raise a problem with a solution in hand, rather than just say "This is a problem, handle it," so my question, after this long tirade, is:     How do you think this can be changed? What would you change in Stack Overflow to make this problem go away without hurting the site?   I promise to vote on answers I like, even if it takes you a long while to post them. :) I am doing some challenges. This is one them. I am trying to brute-force 4 digit pin with the password to get my desired answer. After connecting to the port It prompts me to enter the password then space then 4 digit pin. I tried to brute-force the pin using the script:  #!/bin/bash   nc localhost 30002   sleep 2    for i in {0000..9999};       if [[ $(echo 'UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i' &lt;/dev/stdin) = ^Wrong*]];                         then          continue       echo '[+] Pincode Cracked! Pincode = $i'       fi   done  but it seems that this doesn't input the pass and pin to stdin, before i tried doing something like this -&gt; if [[ $(echo 'UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i') = ^Wrong* ]]; What am I doing wrong here? UPDATE: Okay, so after researching around. I wrote this: for i in {0000..9999} do     if [ (echo &quot;UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i&quot; | nc localhost 30002 | grep -o Wrong) == &quot;Wrong&quot; ]    then       sleep 0.1       continue    fi    echo &quot;- - - - - - - - - - - - - - - - - - - - - - - - [$i]&quot; done  This might even work but as you can see it opens new connections in the loop which makes it really slow and exhaust the system. Possible Duplicate:          I live in a small apartment building and we can catch each-others wifi networks. We have different service provides and were wondering if we could amalgamate our networks so that we could use each others bandwidth transparently.   I would assume this would reduce latency.  Does anybody have a tutorial on how to fuse together wifi networks for a throughput increase? The target machine is a Linux computer.   EDIT  My work makes me do lots of 1TB flat file-transfers, so I believe my motivation is sound. Why is Main method private? I'm using this code to get standard output from an external program:  &gt;&gt;&gt; from subprocess import * &gt;&gt;&gt; command_stdout = Popen(['ls', '-l'], stdout=PIPE).communicate()[0]   The communicate() method returns an array of bytes:  &gt;&gt;&gt; command_stdout b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'   However, I'd like to work with the output as a normal Python string. So that I could print it like this:  &gt;&gt;&gt; print(command_stdout) -rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1 -rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2   I thought that's what the  method is for, but when I tried it, I got the same byte array again:  &gt;&gt;&gt; binascii.b2a_qp(command_stdout) b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'   How do I convert the bytes value back to string? I mean, using the "batteries" instead of doing it manually. And I'd like it to be OK with Python&nbsp;3. Canonical vs. non-canonical terminal input I am studying for an exam and I am confused as to how canonical vs. non-canonical input/output works in Unix (e.g., curses).  I understand that there is a buffer to which "line disciplines" are applied for canonical input.  Does this mean that the buffer is bypassed for non-canonical input, or does it simply mean that no line disciplines are applied?  How does this process differ for input and output operations?  In the curses programs I have worked with that demonstrate canonical input, the input typed by a user is automatically entered either after a certain number of characters have been typed or a certain amount of time has passed.  Are either of these things considered "line disciplines" or is this something else entirely? Is "You are correct" correct? At what port did Lorance Effler born about 1787 in Germany come to the US? Thesis running problem in KILE I'm using  editor. There is no problem when I run others  .tex article in Kile. But problem is when I run a thesis article in KILE. This thesis article is running fine in      \documentclass[12pt,a4paper]{thesis}     \usepackage{amsmath}\usepackage{amssymb}     \usepackage{graphicx}   Is there anything need to add in KILE setting to run the Thesis .tex in KILE?  This is the log file:  This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009/Debian) (format=latex 2013.3.7)  25 AUG 2013 23:37 entering extended mode  %&amp;-line parsing enabled. **Thesis-Aug24-2013.tex (./Thesis-Aug24-2013.tex LaTeX2e &lt;2009/09/24&gt; Babel &lt;v3.8l&gt; and hyphenation patterns for english, usenglishmax, dumylang, noh yphenation, loaded.  ! LaTeX Error: File `thesis.cls' not found.  Type X to quit or &lt;RETURN&gt; to proceed, or enter new name. (Default extension: cls)  Enter file name:  ! Emergency stop. &lt;read *&gt;   l.2 \usepackage                {amsmath}\usepackage{amssymb}^^M *** (cannot \read from terminal in nonstop modes)   Here is how much of TeX's memory you used:  10 strings out of 495062  226 string characters out of 1182645  45108 words of memory out of 3000000  3285 multiletter control sequences out of 15000+50000  3640 words of font info for 14 fonts, out of 3000000 for 9000  28 hyphenation exceptions out of 8191  10i,0n,7p,80b,8s stack positions out of 5000i,500n,10000p,200000b,50000s No pages of output. Show that  $$\frac{\sin x}{\cos 3x}+\frac{\sin 3x}{\cos 9x}+\frac{\sin 9x}{\cos 27x} = \frac{1}{2}\left(\tan 27x-\tan x\right)$$ Isomorphism between quotient modules Is it true for a commutative ring $R$ and its ideals $I$ and $J$ that if the quotient $R$-modules $R/I$ and $R/J$ are isomorphic then $I=J$?