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  • A F# tail-recursive question

    - by ksharp
    Recently, I'm learning F#. I try to solve problem in different ways. Like this: (* [0;1;2;3;4;5;6;7;8] -> [(0,1,2);(3,4,5);(6,7,8)] *) //head-recursive let rec toTriplet_v1 list= match list with | a::b::c::t -> (a,b,c)::(toTriplet_v1 t) | _ -> [] //tail-recursive let toTriplet_v2 list= let rec loop lst acc= match lst with | a::b::c::t -> loop t ((a,b,c)::acc) | _ -> acc loop list [] //tail-recursive(???) let toTriplet_v3 list= let rec loop lst accfun= match lst with | a::b::c::t -> loop t (fun ls -> accfun ((a,b,c)::ls)) | _ -> accfun [] loop list (fun x -> x) let funs = [toTriplet_v1; toTriplet_v2; toTriplet_v3]; funs |> List.map (fun x -> x [0..8]) |> List.iteri (fun i x -> printfn "V%d : %A" (i+1) x) I thought the results of V2 and V3 should be the same. But, I get the result below: V1 : [(0, 1, 2); (3, 4, 5); (6, 7, 8)] V2 : [(6, 7, 8); (3, 4, 5); (0, 1, 2)] V3 : [(0, 1, 2); (3, 4, 5); (6, 7, 8)] Why the results of V2 and V3 are different?

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  • C++ Serial Port Question

    - by Pfeffer
    Problem: I have a hand held device that scans those graphic color barcodes on all packaging. There is a track device that I can use that will slide the device automatically. This track device functions by taking ascii code through a serial port. I need to get this thing to work in FileMaker on a Mac. So no terminal programs, etc... What I've got so far: I bought a Keyspan USB/Serial adapter. Using a program called ZTerm I was successful in sending commands to the device. Example: "C,7^M^J" I was also able to do the same thing in Terminal using this command: screen /dev/tty.KeySerial1 57600 and then type in the same command above(but when I typed in I just hit Control-M and Control-J for the carriage return and line feed) Now I'm writing a plug-in for FileMaker(in C++ of course). I want to get what I did above happen in C++ so when I install that plug-in in FileMaker I can just call one of those functions and have the whole process take place right there. I'm able to connect to the device, but I can't talk to it. It is not responding to anything. I've tried connecting to the device(successfully) using these: FILE *comport; if ((comport = fopen("/dev/tty.KeySerial1", "w")) == NULL){...} and int fd; fd = open("/dev/tty.KeySerial1", O_RDWR | O_NOCTTY | O_NDELAY); This is what I've tried so far in way of talking to the device: fputs ("C,7^M^J",comport); or fprintf(comport,"C,7^M^J"); or char buffer[] = { 'C' , ',' , '7' , '^' , 'M' , '^' , 'J' }; fwrite (buffer , 1 , sizeof(buffer) , comport ); or fwrite('C,7^M^J', 1, 1, comport); Questions: When I connected to the device from Terminal and using ZTerm, I was able to set my baud rate of 57600. I think that may be why it isn't responding here. But I don't know how to do it here.... Does any one know how to do that? I tried this, but it didn't work: comport->BaudRate = 57600; There are a lot of class solutions out there but they all call these include files like termios.h and stdio.h. I don't have these and, for whatever reason, I can't find them to download. I've downloaded a few examples but there are like 20 files in them and they're all calling other files I can't find(like the ones listed above). Do I need to find these and if so where? I just don't know enough about C++ Is there a website where I can download libraries?? Another solution might be to put those terminal commands in C++. Is there a way to do that? So this has been driving me crazy. I'm not a C++ guy, I only know basic programming concepts. Is anyone out there a C++ expert? I ideally I'd like this to just work using functions I already have, like those fwrite, fputs stuff. Thanks!

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  • Question with "extern" in C

    - by why
    When programming, I would like to split one large file(which contains main function) to many small files, so there is one common case: functions in small files can modify the var from main file, so i think extern is very useful! for instance: in main.c extern int i = 100; in small.c extern int i; fprintf(stdout, "var from main file: %d\n", i); I just want to know is my understanding right?

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  • General question: Filesystem or database?

    - by poeschlorn
    Hey guys, i want to create a small document management system. there are several users who store their files. each file which is uploaded contains an info which user uploaded it and the document content itself. In a view there are displayed all files of ONE specific user, ordered by date. What would be better: 1) giving the documents a name or metadata(XML) which contain the date and user (and iterate through them to get the metadata) or 2) giving the files a random/unique name and store metadata in a DB? something like this: date | user | filename What would you say and why? The used programming language is java and the DB is MySQL.

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  • CodeIgniter Question: How to delete records using ActiveRecord with mySQL function as WHERE conditio

    - by Jhourlad Estrella
    I have a table named ChatSessions where I keep track of active users in the chatroom. I need to prune expired user sessions from the table every 10 minutes. Using pure php-mysql is plain simple but I'm totally clueless how to convert this into ActiveRecord in CodeIgniter. The plain SQL query is below: SELECT * FROM `ChatSessions` WHERE `SessionExpires` < DATE_SUB( NOW( ) , INTERVAL 10 MINUTE ) Can anybody tell me what is the equivalent code in CodeIgniter using ActiveRecord? Thanks in advanced.

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  • Design question - loading info from DB

    - by eriks
    I need to build a class that will represent a row in some table in DB (lets say the table is 'Subscriber' and so is the class). I can have the class Subscriber which constructor receives the Objectkey of subscriber, retrieves info from DB and initializes its members. I add another class - SubscriberLoader which have a static method 'LoadSubscriber'. This method will receive the subscriber objectkey, retrieve info from DB, crate a Subscriber object and initialize its members. Subscriber constructor will be private and SubscirberLoader will be friend class of Subscriber - this way, client could build a Subscriber only using the loader. which of the two in better? any other suggestions?

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  • Beginner Design pattern question (Web Services involved)

    - by zombie
    Hi all ! I am a noob to web services world. I need to develop a login validator module and expose it as a service. I want it to be service independent, i.e I should have the option of exposing it as a SOAP service or REST service in the future. What pattern should I follow ? Sorry if I am unclear in my requirements, I can clarify as per need. Thanks !! Edit : I am using Eclipse as an IDE and Jersey libraries. I am not into any framework, simply using the MVC pattern. I find a lot of difference between SOAP ann REST methods, so I want my methods to be implementation independent - i.e I should be easily able to use my method through a SOAP or REST service call as per need. What should I do for maximum flexibility ?

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  • CSS Float left question

    - by Minghui Yu
    <div id="slideshow-prevnext" class="slideshow-prevnext"> <a id="prev" class="left" href="#"><span class="invisible">Prev</span></a> <a id="next" class="right" href="#"><span class="invisible">Next</span></a> <a href="#" class="dot">&nbsp;</a> <a href="#" class="dot">&nbsp;</a> <a href="#" class="dot">&nbsp;</a> </div> I want the three <a href="#" class="dot">&nbsp;</a> appear on the left of and the two ("Prev" and "Next") on the right. How can I do it? I tried float:left but does not work. Edit: CSS is too long to post. Development site is here at : http://site2.ewart.library.ubc.ca/

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  • A beginner's log4J question

    - by Nitesh Panchal
    Hello, i configured log4j for basic purpose usin the conversion pattern :- log4j.appender.rollingFile.layout.ConversionPattern=%p %t %c - %m%n But now i want to log the class name from which the error came as well as the username(available in session object) as well as the date and time when that event occurs. How do i do this? What changes do i need to make in format string? Thanks in advance :)

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  • WCF host address question

    - by Estelle
    when I setup the wcf service on a web server, I set the end point address as <endpoint address="http://www.mydomin.com/clientname/happy.svc" binding="basicHttpBinding" name="happysvcbasic" contract="happysvc.Ihappysvc"> </endpoint> but when type in above address on a browser, I get a different host name, which is the internal server name, such as, To test this service, you will need to create a client and use it to call the service. You can do this using the svcutil.exe tool from the command line with the following syntax: svcutil.exe http://internalservername.domain/clientname/happy.svc?wsdl I tried to add the host/baseaddress tag, but make no difference, what I missed? thanks for help.

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  • Question on Split usage in Perl

    - by Nano HE
    Hello. I wrote an small script to use Split() as this, use strict; use warnings; use Data::Dumper; my $fh = \*DATA; while(my $line = <$fh>) { my @values = split(':', $line); foreach my $val (@values) { print "$val\n"; } } __DATA__ 1 : Hello World String10 : NO : A1B2,B3 11 : Hello World String11 : YES : A11B2,B3,B14,B25 A1B2,B3 and A11B2,B3 are characters form like Only One Letter A and One or Two Number 2, 3, 14,25 etc then concatenated with Only One Letter B and one or two Numbers like 2, 3, 14,25. etc Now out put as this 1 Hello World String10 NO A1B2,B3 11 Hello World String11 YES A11B2,B3,B14,B25 How can I hold the last array member from @values and made concatenation and out put as this. 1 Hello World String1 NO A1B2,A1B3 11 Hello World String11 YES A11B2,A11B3,A11B14,A11B25 Appreciated for your comments and replies. [update] My out put need the concatenation followed the rule. A and one or two numbers and joined by B and one or two numbers split by ,

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  • Java Swing: JTextArea columns question

    - by battousai622
    How do i put the text in specific columns with jTextArea? private javax.swing.JTextArea jTextArea1; jTextArea1.setColumns(4); jTextArea1.insert(price, 0); //column 1 jTextArea1.insert(cost, 0); //column 2 jTextArea1.insert(quantity, 0); //column ect.. jTextArea1.insert(itemName, 0); jTextArea1.insert("\n", 0);

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  • interactive login on perl cgi script- updated question [closed]

    - by raindrop18
    I am new for perl-cgi script. and my objective is to create user/pass interactive script to log and get information from multiple device at once. instead of add the user/pass credential on the script itself. since i am new if some one show me how to write the interactive part of the script. thanks much!!! here is the current code usr/local/bin/perl -wl use CGI ':standard'; use Net::Telnet::Cisco; # ### set the error fields to nulls $selerror = ""; # ### Input from the screen - make sure data was input if (param() and param('Switches') ne "" and (param('Mac') ne "" or param('Interface Description') ne "" or param('VLAN') ne "" )) { # ### Put the input devices into an array. @devices = param('Switches'); # ### format the header data print header(); print start_html(-title=>"ShowSwitches",-BGCOLOR=>'aqua'); print "\n",h1("<CENTER>Show Switches</CENTER>"); print "\n",hr(),"\n"; # ### Go thru the device array. foreach(@devices) { $error_msg = ""; $TAC_login_error = ""; $open_error = ""; $retry_open_error = ""; $prompt_error = ""; $password_error = ""; # ### Take input host and use to send to Telnet $host = $_; $session = Net::Telnet::Cisco->new(Errmode => 'return', Timeout => 30); # ### Connect to the host $session->open(Host =>"$host", Timeout => 15); $open_error = $session->errmsg; # ### Login with TACACS if host can be connected to if ($open_error eq "") { $session->login('USER', 'PASS'); $TAC_login_error = $session->errmsg; # ### Login with TACACS failed - try standard login if ($TAC_login_error ne "") { # ### Connect to host $session->open(Host =>"$host", Timeout => 15); $retry_open_error = $session->errmsg; # ### Wait for password prompt - multiple matches - devices may have different device prompts. if ($retry_open_error eq "") { $session->waitfor(Match => '/Password:.*$/', Match => '/Enter password:.*$/', Timeout => 20); $prompt_error = $session->errmsg; if ($prompt_error eq "") { # ### Input password $session->print('getmeout'); $password_error = $session->errmsg; $session->waitfor('/.*>$/'); $password_error = $session->errmsg; } } } } # ### No errors, then issue "show commands". if ($open_error eq "" and ($TAC_login_error eq "" or $retry_open_error eq "") and $prompt_error eq "" and $password_error eq "") { # ### Show Mac if (param('Mac')) { $cmd = 'sh mac'; @output = $session->cmd("$cmd"); $show_error = ""; $show_error = $session->errmsg; print "\n",h2($host . ' - ' . $cmd); if ($show_error ne "") { $error_msg = 'Error for show mac - ' . $show_error; print b($error_msg),(br); print hr(),"\n"; $error_msg = ''; } else { print pre(@output); print hr(),"\n"; } } # ### Show Interface Description if (param('Interface Description')) { $cmd = 'sh interface description'; @output = $session->cmd("$cmd"); $show_error = ""; $show_error = $session->errmsg; print "\n",h2($host . ' - ' . $cmd); if ($show_error ne "") { $error_msg = 'Error for show mac - ' . $show_error; print b($error_msg),(br); print hr(),"\n"; $error_msg = ''; } else { print pre(@output); print hr(),"\n"; } } # ### Show VLAN if (param('VLAN')) { $cmd = 'sh vlan'; @output = $session->cmd("$cmd"); $show_error = ""; $show_error = $session->errmsg; print "\n",h2($host . ' - ' . $cmd); if ($show_error ne "") { $error_msg = 'Error for show vlan - ' . $show_error; print b($error_msg),(br); print hr(),"\n"; $error_msg = ''; } else { print pre(@output); print hr(),"\n"; } } } elsif ($TAC_login_error ne "" and $password_error ne "") { $error_msg = "Error - $host " . $TAC_login_error . ' - possible incorrect TACACS or standard password parameters on device.'; } elsif ($open_error ne "") { $error_msg = "Error - $host " . $open_error . ' - cannot connect to host - is it down??'; } elsif ($prompt_error ne "") { $error_msg = "Error - $host " . $prompt_error . ' - password prompt not recognized - invalid TACACS (or user) password.'; } elsif ($password_error ne "") { $error_msg = "Error - $host " . $password_error . ' - possible incorrect user/password parameters on device.'; } if ($error_msg ne "" ) { print b($error_msg),(br); print hr(),"\n"; } print hr(),"\n"; print end_html(),"\n"; } } else { # ### No Show command was selected. if (param('Submit') and param('Mac') eq "" and param('Interface Description') eq "" and param('VLAN') eq "" ) { $selerror = 'No Show Displays were selected. Try again please!!'; } elsif # ### No switch was selected. (param('Submit') and param('Switches') eq "") { $selerror = 'No devices were selected. Try again please!!'; } # ### This formats the initial Show Web page. print header(-Pragma=>'no-cache'), start_html(-title=>"Show Displays",-BGCOLOR=>'aqua'), h1("<CENTER>Show Switches</CENTER>"),hr(), start_form(), b("Select Show Commands:"), br(), br(), checkbox(-name=>'Mac'), checkbox(-name=>'Interface Description'), checkbox(-name=>'VLAN'), br(),br(),hr(),br(), b("Select One or More Devices:"), br(), br(), scrolling_list (-name => 'Switches', -default=> "NONE", -values => ['cs6a', 'cs7a', 'cs7b', 'cs8b', 'cs9a', 'c9b', 'csa' ], -multiple => 'true', -size => 7, ), p(submit('Submit'),reset('Reset')), b($selerror), end_form(),hr(), end_html(); } #

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  • Simple Ruby Command Line Question

    - by aronchick
    Um - I feel like an idiot, but.... ruby -e '3+5' Outputs nothing (Windows 7, Ruby 1.8.7, Cygwin or Git Bash). What am I missing? Extra credit - will this also allow the extra cool bundle (stolen from TextMate) Execute and Update # = markers to work properly? EDIT Ok that worked, and I'll accept the answer, but e-texteditor still doesn't work with that really cool bundle. Too bad.

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  • MySQL table data question?

    - by mySQL
    How should my Mysql table data look like for a single checkbox that checks and see if the user has said yes if its clicked or no if its not? Here is the checkbox. <input type="checkbox" name="yes" id="yes" value="yes" /> I was wondering how would I add it to the following table. CREATE TABLE IF NOT EXISTS `vote` ( `counter` int(8) NOT NULL default '0', `value` int(8) NOT NULL default '0' ) ENGINE=MyISAM DEFAULT CHARSET=latin1;

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  • question about missing element in array

    - by davit-datuashvili
    i have following problem from book introduction algorithm second edition by MIT university problem is following An array A[1 . . n] contains all the integers from 0 to n except one. It would be easy to determine the missing integer in O(n) time by using an auxiliary array B[0 . . n] to record which numbers appear in A. In this problem, however, we cannot access an entire integer in A with a single operation. The elements of A are represented in binary, and the only operation we can use to access them is “fetch the j th bit of A[i],” which takes constant time. Show that if we use only this operation, we can still determine the missing inte- ger in O(n) time please help

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  • Question about TerminateProcess hook

    - by imans62
    I wrote this code but it does not work correctly - can you help me? void EnableDebugPriv() { HANDLE hToken; LUID luid; TOKEN_PRIVILEGES tkp; OpenProcessToken( GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken ); LookupPrivilegeValue( NULL, SE_DEBUG_NAME, &luid ); tkp.PrivilegeCount = 1; tkp.Privileges[0].Luid = luid; tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED; AdjustTokenPrivileges( hToken, false, &tkp, sizeof( tkp ), NULL, NULL ); CloseHandle( hToken ); } NTSTATUS WINAPI HookedNtTerminateProcess( __in HANDLE hProcess, __in UINT uExitCode ) { NTSTATUS statues = OriginalNtTerminateProcess(hProcess,uExitCode); HANDLE hProc; PROCESSENTRY32 entry; entry.dwFlags = sizeof( PROCESSENTRY32 ); HANDLE snapshot = CreateToolhelp32Snapshot( TH32CS_SNAPPROCESS, NULL ); if ( Process32First( snapshot, &entry ) == TRUE ) { while ( Process32Next( snapshot, &entry ) == TRUE ) { if ( wcsicmp( entry.szExeFile, L"calc.exe" ) == 0 ) { EnableDebugPriv(); HANDLE hProc = OpenProcess( PROCESS_ALL_ACCESS, FALSE, entry.th32ProcessID ); // Do stuff.. //CloseHandle( hProc ); } } } if(hProc == hProcess) MessageBox(NULL, L"Error", L"Information", MB_OK); else TerminateProcess(hProcess,uExitCode); CloseHandle( hProc); CloseHandle( snapshot ); return statues; }

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  • waveInProc / Windows audio question...

    - by BTR
    I'm using the Windows API to get audio input. I've followed all the steps on MSDN and managed to record audio to a WAV file. No problem. I'm using multiple buffers and all that. I'd like to do more with the buffers than simply write to a file, so now I've got a callback set up. It works great and I'm getting the data, but I'm not sure what to do with it once I have it. Here's my callback... everything here works: // Media API callback void CALLBACK AudioRecorder::waveInProc(HWAVEIN hWaveIn, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2) { // Data received if (uMsg == WIM_DATA) { // Get wav header LPWAVEHDR mBuffer = (WAVEHDR *)dwParam1; // Now what? for (unsigned i = 0; i != mBuffer->dwBytesRecorded; ++i) { // I can see the char, how do get them into my file and audio buffers? cout << mBuffer->lpData[i] << "\n"; } // Re-use buffer mResultHnd = waveInAddBuffer(hWaveIn, mBuffer, sizeof(mInputBuffer[0])); // mInputBuffer is a const WAVEHDR * } } // waveInOpen cannot use an instance method as its callback, // so we create a static method which calls the instance version void CALLBACK AudioRecorder::staticWaveInProc(HWAVEIN hWaveIn, UINT uMsg, DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD_PTR dwParam2) { // Call instance version of method reinterpret_cast<AudioRecorder *>(dwParam1)->waveInProc(hWaveIn, uMsg, dwInstance, dwParam1, dwParam2); } Like I said, it works great, but I'm trying to do the following: Convert the data to short and copy into an array Convert the data to float and copy into an array Copy the data to a larger char array which I'll write into a WAV Relay the data to an arbitrary output device I've worked with FMOD a lot and I'm familiar with interleaving and all that. But FMOD dishes everything out as floats. In this case, I'm going the other way. I guess I'm basically just looking for resources on how to go from LPSTR to short, float, and unsigned char. Thanks much in advance!

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  • Code refactoring c# question around several if statements performing the same check

    - by James Radford
    I have a method that has a load of if statements that seems a bit silly although I'm not sure how to improve the code. Here's an example. This logic was inside the view which is now in the controller which is far better but is there something I'm missing, maybe a design pattern that stops me having to check against panelCount < NumberOfPanelsToShow and handling the panelCount every condition? Maybe not, just feels ugly! Many thanks if (model.Train && panelCount < NumberOfPanelsToShow) { panelTypeList.Add(TheType.Train); panelCount++; } if (model.Car && panelCount < NumberOfPanelsToShow) { panelTypeList.Add(TheType.Car); panelCount++; } if (model.Hotel && panelCount < NumberOfPanelsToShow) { panelTypeList.Add(TheType.Hotel); panelCount++; } ...

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  • A question related to UITextfield

    - by user217572
    I have UITextfiled created dynamically by code I want to move keyboard up on click of UITextfield It should be set wether the return button of UITextfield press or not? and also it will be set whenever i move from portrait to landscape or landscape to portrait mode

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  • Quick CPU ring mode protection question

    - by b-gen-jack-o-neill
    Hi, me again :) I am very curious in messing up with HW. But my top level "messing" so far was linked or inline assembler in C program. If my understanding of CPU and ring mode is right, I cannot directly from user mode app access some low level CPU features, like disabling interrupts, or changing protected mode segments, so I must use system calls to do everything I want. But, if I am right, drivers can run in ring mode 0. I actually don´t know much about drivers, but this is what I ask for. I just want to know, is learning how to write your own drivers and than call them the way I should go, to do what I wrote? I know I could write whole new OS (at least to some point), but what I exactly want to do is acessing some low level features of HW from standart windows application. So, is driver the way to go?

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  • Question about char input

    - by DomX23
    This is what I'm trying to do... char input[4]; cin >> input; cout << "Input[0]: " << input[0] << "Input[1]: " << input[1] << "Input[2]: " << input[2] << "Input[3] " << input[3]<< "Input[4] " << input[4] <<endl; However, when I enter "P F" I get an out of this: Input[0]:P Input[1]: Input[2]: Input[3] Input[4] Why do I get that weird character instead of F?

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