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  • Whats the wrong with this code?

    - by girinie
    Hi in this code first I am downloading a web-page source code then I am storing the code in text file. Again I am reading that file and matching with the regex to search a specific string. There is no compiler error. Exception in thread "main" java.lang.NoClassDefFoundError: java/lang/CharSequence Can anybody tell me Where I am wrong. import java.io.*; import java.net.*; import java.lang.*; import java.util.regex.Matcher; import java.util.regex.Pattern; public class WebDownload { public void getWebsite() { try{ URL url=new URL("www.gmail.com");// any URL can be given URLConnection urlc=url.openConnection(); BufferedInputStream buffer=new BufferedInputStream(urlc.getInputStream()); StringBuffer builder=new StringBuffer(); int byteRead; FileOutputStream fout; StringBuffer contentBuf = new StringBuffer(); while((byteRead=buffer.read()) !=-1) { builder.append((char)byteRead); fout = new FileOutputStream ("myfile3.txt"); new PrintStream(fout).println (builder.toString()); fout.close(); } BufferedReader in = new BufferedReader(new FileReader("myfile3.txt")); String buf = null; while ((buf = in.readLine()) != null) { contentBuf.append(buf);contentBuf.append("\n"); } in.close(); Pattern p = Pattern.compile("<div class=\"summarycount\">([^<]*)</div>"); Matcher matcher = p.matcher(contentBuf); if(matcher.find()) { System.out.println(matcher.group(1)); } else System.out.println("could not find"); } catch(MalformedURLException ex) { ex.printStackTrace(); } catch(IOException ex){ ex.printStackTrace(); } } public static void main(String [] args) { WebDownload web=new WebDownload(); web.getWebsite(); } }

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  • sizeof abuse : get the size of a const table

    - by shodanex
    When declaring a const table, it is possible to get the size of the table using sizeof. However, once you stop using the symbol name, it does not work anymore. is there a way to have the following program output the correct size for table A, instead of 0 ? #include <stdio.h> struct mystruct { int a; short b; }; const struct mystruct tableA[] ={ { .a = 1, .b = 2, }, { .a = 2, .b = 2, }, { .a = 3, .b = 2, }, }; const struct mystruct tableB[] ={ { .a = 1, .b = 2, }, { .a = 2, .b = 2, }, }; int main(int argc, char * argv[]) { int tbl_sz; const struct mystruct * table; table = tableA; tbl_sz = sizeof(table)/sizeof(struct mystruct); printf("size of table A : %d\n", tbl_sz); table = tableB; tbl_sz = sizeof(tableB)/sizeof(struct mystruct); printf("size of table B : %d\n", tbl_sz); return 0; } Output is : size of table A : 0 size of table B : 2

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  • ASP.NET MVC Map String Url To A Route Value Object

    - by mwgriffiths
    I am creating a modular ASP.NET MVC application using areas. In short, I have created a greedy route that captures all routes beginning with {application}/{*catchAll}. Here is the action: // get /application/index public ActionResult Index(string application, object catchAll) { // forward to partial request to return partial view ViewData["partialRequest"] = new PartialRequest(catchAll); // this gets called in the view page and uses a partial request class to return a partial view } Example: The Url "/Application/Accounts/LogOn" will then cause the Index action to pass "/Accounts/LogOn" into the PartialRequest, but as a string value. // partial request constructor public PartialRequest(object routeValues) { RouteValueDictionary = new RouteValueDictionary(routeValues); } In this case, the route value dictionary will not return any values for the routeData, whereas if I specify a route in the Index Action: ViewData["partialRequest"] = new PartialRequest(new { controller = "accounts", action = "logon" }); It works, and the routeData values contains a "controller" key and an "action" key; whereas before, the keys are empty, and therefore the rest of the class wont work. So my question is, how can I convert the "/Accounts/LogOn" in the catchAll to "new { controller = "accounts", action = "logon" }"?? If this is not clear, I will explain more! :) Matt This is the "closest" I have got, but it obviously wont work for complex routes: // split values into array var routeParts = catchAll.ToString().Split(new char[] { '/' }, StringSplitOptions.RemoveEmptyEntries); // feels like a hack catchAll = new { controller = routeParts[0], action = routeParts[1] };

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  • How to Implement Grep into CGI script Please?

    - by Joey jie
    Hi all! I am having difficulty figuring out how to implement grep into my CGI script. Basically I will receive a value of eg. 1500 from a HTML page. The CGI script then runs and compares 1500 to a text file. When it finds 1500 it prints the entire line and displays it on the webpage. I would like some tips and pointers on how to do this please. I understand that this involves grep but I don't really know how to put it in. #include <stdio.h> #include <stdlib.h> int main(void) { char *data; long m,n; printf("%s%c%c\n", "Content-Type:text/html;charset=iso-8859-1",13,10); printf("<TITLE>Webpage of Results</TITLE>\n"); printf("<H1>Temperatures</H1>\n"); data = getenv("QUERY_STRING"); The HTML passes the variable time=1500. I understand (correct me if I am wrong) that QUERY_STRING will contain 1500?

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  • Primefaces push encoding

    - by kalaoke
    I use primefaces push to write a message in a p:notificationBar. if i push a message with specials characters (like russians char), I've got '?' in my message. How can I fix this problem ? Thanks for your help. (config : primefaces 3.4 and jsf2. All my html pages are utf8 encoding). Here is my view code : <p:notificationBar id="bar" widgetVar="pushNotifBar" position="bottom" style="z-index: 3;border: 8px outset #AB1700;width: 97%;background: none repeat scroll 0 0 #CA837D;"> <h:form prependId="false"> <p:commandButton icon="ui-icon-close" title="#{messages['gen.close']}" styleClass="ui-notificationbar-close" type="button" onclick="pushNotifBar.hide();"/> </h:form> <h:panelGrid columns="1" style="width: 100%; text-align: center;"> <h:outputText id="pushNotifSummary" value="#{growlBean.summary}" style="font-size:36px;text-align:center;"/> <h:outputText id="pushNotifDetail" value="#{growlBean.detail}" style="font-size: 20px; float: left;" /> </h:panelGrid> </p:notificationBar> <p:socket onMessage="handleMessage" channel="/notifications"/> <script type="text/javascript"> function handleMessage(data) { var substr = data.split(' %% '); $('#pushNotifSummary').html(substr[0]); $('#pushNotifDetail').html(substr[1]); pushNotifBar.show(); } </script> and my Bean code : public void send() { PushContext pushContext = PushContextFactory.getDefault().getPushContext(); String var = summary + " %% " + detail; pushContext.push("/notifications", var);

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  • Pointers in C# to make int array?

    - by Joshua
    The following C++ program compiles and runs as expected: #include <stdio.h> int main(int argc, char* argv[]) { int* test = new int[10]; for (int i = 0; i < 10; i++) test[i] = i * 10; printf("%d \n", test[5]); // 50 printf("%d \n", 5[test]); // 50 return getchar(); } The closest C# simple example I could make for this question is: using System; class Program { unsafe static int Main(string[] args) { // error CS0029: Cannot implicitly convert type 'int[]' to 'int*' int* test = new int[10]; for (int i = 0; i < 10; i++) test[i] = i * 10; Console.WriteLine(test[5]); // 50 Console.WriteLine(5[test]); // Error return (int)Console.ReadKey().Key; } } So how do I make the pointer?

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  • Help regarding Android NDK

    - by Siva Kumar
    I am a beginner in using Android NDK. I am using Eclipse and I installed cygwin to build the c file to generate the .so file But while building the c file in cygwin I am always getting the error make: ***No rule to make target 'file.c' ... .Stop I tried building different C codes but for every file it says the same error .. Here is the source code: public class ndktest extends Activity { static { System.loadLibrary("ndkt"); } private native void helloLog(String logThis); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); helloLog("this is to test log file"); } } file.c void Java_com_ndktest_helloLog(JNIEnv * env, jobject this, jstring logThis) { jboolean isCopy; const char * szLogThis = (*env)->GetStringUTFChars(env, logThis, &isCopy); (*env)->ReleaseStringUTFChars(env, logThis, szLogThis); } And here is my Android.mk LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_LDLIBS := -llog LOCAL_MODULE := ndkt LOCAL_SRC_FILES := file.c include $(BUILD_SHARED_LIBRARY) I searched for the solution for the cause of error ... but nothing works for me. Can anyone tell me where I am making the mistake ? Thanks, Siva Kumar

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  • Mysql error in stored procudure

    - by devuser
    This stored procedure is to search through all tables and columns in database. DELIMITER $$ DROP PROCEDURE IF EXISTS get_table $$ CREATE /*[DEFINER = { user | CURRENT_USER }]*/ PROCEDURE `auradoxdb`.`get_table`(in_search varchar(50)) READS SQL DATA BEGIN DECLARE trunc_cmd VARCHAR(50); DECLARE search_string VARCHAR(250); DECLARE db,tbl,clmn CHAR(50); DECLARE done INT DEFAULT 0; DECLARE COUNTER INT; DECLARE table_cur CURSOR FOR SELECT concat(SELECT COUNT(*) INTO @CNT_VALUE FROM `’,table_schema,’`.`’,table_name,’` WHERE `’, column_name,’` REGEXP ”’,in_search,”’) ,table_schema,table_name,column_name FROM information_schema.COLUMNS WHERE TABLE_SCHEMA NOT IN (‘information_schema’,'test’,'mysql’); DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1; # #Truncating table for refill the data for new search. PREPARE trunc_cmd FROM “TRUNCATE TABLE temp_details;” EXECUTE trunc_cmd ; OPEN table_cur; table_loop:LOOP FETCH table_cur INTO search_string,db,tbl,clmn; # #Executing the search SET @search_string = search_string; SELECT search_string; PREPARE search_string FROM @search_string; EXECUTE search_string; SET COUNTER = @CNT_VALUE; SELECT COUNTER; IF COUNTER>0 THEN # # Inserting required results from search to tablehhh INSERT INTO temp_details VALUES(db,tbl,clmn); END IF; IF done=1 THEN LEAVE table_loop; END IF; END LOOP; CLOSE table_cur; # #Finally Show Results SELECT * FROM temp_details; END $$ DELIMITER ; Following error occurs when execute this.. Error Code : 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT COUNT(*) INTO @CNT_VALUE FROM `’,table_schema,’`.`’,table_name,’`' at line 12 (0 ms taken) could any body please help me to solve this?

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  • Creating a QMainWindow from Java using JNI

    - by ebasconp
    Hi everybody: I'm trying to create a Qt main windows from Java using JNI directly and I got a threading error. My code looks like this: Test class: public class Test { public static void main(String... args) { System.out.println(System.getProperty("java.library.path")); TestWindow f = new TestWindow(); f.show(); } } TestWindow class: public class TestWindow { static { System.loadLibrary("mylib"); } public native void show(); } C++ impl: void JNICALL Java_testpackage_TestWindow_show (JNIEnv *, jobject) { int c = 0; char** a = NULL; QApplication* app = new QApplication(c, a); QMainWindow* mw = new QMainWindow(); mw->setWindowTitle("Hello"); mw->setGeometry(150, 150, 400, 300); mw->show(); QApplication::exec(); } and I get my window painted but frozen (it does not receive any event) and the following error message when instantiating the QMainWindow object: QCoreApplication::sendPostedEvents: Cannot send posted events for objects in another thread I know all the UI operations must done in the UI thread but in my example I created the QApplication in the only thread I have running, so, everything should work properly. I did some tests executing the code of my "show" method from a QMetaObject::invokeMethod stuff using Qt::QueuedConnection but nothing works properly. I know I could use Jambi... but I know that it could be done natively too and that is what I want to do :) Any ideas on this? Thanks in advance! Ernesto

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  • If the address of a function can not be resolved during deduction, is it SFINAE or a compiler error?

    - by Faisal Vali
    In C++0x SFINAE rules have been simplified such that any invalid expression or type that occurs in the "immediate context" of deduction does not result in a compiler error but rather in deduction failure (SFINAE). My question is this: If I take the address of an overloaded function and it can not be resolved, is that failure in the immediate-context of deduction? (i.e is it a hard error or SFINAE if it can not be resolved)? Here is some sample code: struct X { // template T* foo(T,T); // lets not over-complicate things for now void foo(char); void foo(int); }; template struct S { template struct size_map { typedef int type; }; // here is where we take the address of a possibly overloaded function template void f(T, typename size_map::type* = 0); void f(...); }; int main() { S s; // should this cause a compiler error because 'auto T = &X::foo' is invalid? s.f(3); } Gcc 4.5 states that this is a compiler error, and clang spits out an assertion violation. Here are some more related questions of interest: Does the FCD-C++0x clearly specify what should happen here? Are the compilers wrong in rejecting this code? Does the "immediate-context" of deduction need to be defined a little better? Thanks!

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  • Socket Communication in iPhone

    - by Timmi
    I have many images in iPhone. I have to send this images to server using a socket communication. what all we need to do to send the images to server through socket. If i use this code i can send string. what all should i change in the code so that i can send image through socket. I am new to network programming so some please help me to find a solution CFWriteStreamRef writeStream = NULL; CFStringRef host = CFSTR("192.168.1.211"); UInt32 port = 8001; CFStreamCreatePairWithSocketToHost(kCFAllocatorDef ault, host, port, NULL, &writeStream); CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue); if(!CFWriteStreamOpen(writeStream)) { NSLog(@"Error Opening Socket"); } else{ UInt8 buf[] = "Hi !!!"; int bytesWritten = CFWriteStreamWrite(writeStream, buf, strlen((char*)buf)); NSLog(@"Written: %d", bytesWritten); if (bytesWritten < 0) { CFStreamError error = CFWriteStreamGetError(writeStream); } } Thanks,

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  • extern and global in c

    - by JPro
    Can anyone please tell me is there any special requirement to use either EXTERN or GLOBAL variables in a C program? I do not see any difference in a program like below, if I change from gloabl to extern. #include <stdio.h> #include <stdlib.h> int myGlobalvar = 10; int main(int argc, char *argv[]) { int myFunc(int); int i; i = 12; myGlobalvar = 100; printf("Value of myGlobalvar is %d , i = %d\n", myGlobalvar, i); i = myFunc(10); printf("Value of passed value : %d\n",i); printf("again Value of myGlobalvar is %d , i = %d\n", myGlobalvar, i); system("PAUSE"); return 0; } int myFunc(int i) { i = 20 + 1000; //extern int myGlobalvar; myGlobalvar = 20000; // printf("Value of passed value : %d",i); return i; } If uncomment extern int myGlobalvar, the value does not change. Is there any correct difference between both? Can anyone please correct me?

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  • C# TcpClient, getting back the entire response from a telnet device

    - by Dan Bailiff
    I'm writing a configuration tool for a device that can communicate via telnet. The tool sends a command via TcpClient.GetStream().Write(...), and then checks for the device response via TcpClient.GetStream().ReadByte(). This works fine in unit tests or when I'm stepping through code slowly. If I run the config tool such that it performs multiple commands consecutively, then the behavior of the read is inconsistent. By inconsistent I mean sometimes the data is missing, incomplete or partially garbled. So even though the device performed the operation and responded, my code to check for the response was unreliable. I "fixed" this problem by adding a Thread.Sleep to make sure the read method waits long enough for the device to complete its job and send back the whole response (in this case 1.5 seconds was a safe amount). I feel like this is wrong, blocking everything for a fixed time, and I wonder if there is a better way to get the read method to wait only long enough to get the whole response from the device. private string Read() { if (!tcpClient.Connected) throw (new Exception("Read() failed: Telnet connection not available.")); StringBuilder sb = new StringBuilder(); do { ParseTelnet(ref sb); System.Threading.Thread.Sleep(1500); } while (tcpClient.Available > 0); return sb.ToString(); } private void ParseTelnet(ref StringBuilder sb) { while (tcpClient.Available > 0) { int input = tcpClient.GetStream().ReadByte(); switch (input) { // parse the input // ... do other things in special cases default: sb.Append((char)input); break; } } }

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  • PHP Unicode character questions

    - by user271619
    Here's a link I found, which even has a character I need to play with for other projects of mine. http://www.fileformat.info/info/unicode/char/2446/index.htm There is a box with the Title of: "Encodings" on that page. And I am wondering about some of the rows. I obviously need a course on this sort of thing, but I'm wondering what the difference is between "HTML Entity (decimal)" and "HTML Entity (hex)". The funny thing is, which confuses me, I throw those characters on a web page, and they display fine. But I haven't specified any UTF-8 encoding in the php page. <?php $string1 = '&#x2446;'; $string2 = '&#9286;'; echo $string1; echo '<br>'; echo $string2; ?> Does the browser know how to display both automatically? And to make it weirder, I can only see those characters on my Mac, in Firefox. But my windows box doesn't want to show them. I've tested it in chrome, and firefox. Do I need to tell the browsers to view them correctly? Or is it an operating system modification?

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  • Suggestions of the easiest algorithms for some Graph operations

    - by Nazgulled
    Hi, The deadline for this project is closing in very quickly and I don't have much time to deal with what it's left. So, instead of looking for the best (and probably more complicated/time consuming) algorithms, I'm looking for the easiest algorithms to implement a few operations on a Graph structure. The operations I'll need to do is as follows: List all users in the graph network given a distance X List all users in the graph network given a distance X and the type of relation Calculate the shortest path between 2 users on the graph network given a type of relation Calculate the maximum distance between 2 users on the graph network Calculate the most distant connected users on the graph network A few notes about my Graph implementation: The edge node has 2 properties, one is of type char and another int. They represent the type of relation and weight, respectively. The Graph is implemented with linked lists, for both the vertices and edges. I mean, each vertex points to the next one and each vertex also points to the head of a different linked list, the edges for that specific vertex. What I know about what I need to do: I don't know if this is the easiest as I said above, but for the shortest path between 2 users, I believe the Dijkstra algorithm is what people seem to recommend pretty often so I think I'm going with that. I've been searching and searching and I'm finding it hard to implement this algorithm, does anyone know of any tutorial or something easy to understand so I can implement this algorithm myself? If possible, with C source code examples, it would help a lot. I see many examples with math notations but that just confuses me even more. Do you think it would help if I "converted" the graph to an adjacency matrix to represent the links weight and relation type? Would it be easier to perform the algorithm on that instead of the linked lists? I could easily implement a function to do that conversion when needed. I'm saying this because I got the feeling it would be easier after reading a couple of pages about the subject, but I could be wrong. I don't have any ideas about the other 4 operations, suggestions?

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  • Template operator linker error

    - by Dani
    I have a linker error I've reduced to a simple example. The build output is: debug/main.o: In function main': C:\Users\Dani\Documents\Projects\Test1/main.cpp:5: undefined reference tolog& log::operator<< (char const (&) [6])' collect2: ld returned 1 exit status It looks like the linker ignores the definition in log.cpp. I also cant put the definition in log.h because I include the file alot of times and it complains about redefinitions. main.cpp: #include "log.h" int main() { log() << "hello"; return 0; } log.h: #ifndef LOG_H #define LOG_H class log { public: log(); template<typename T> log &operator <<(T &t); }; #endif // LOG_H log.cpp: #include "log.h" #include <iostream> log::log() { } template<typename T> log &log::operator <<(T &t) { std::cout << t << std::endl; return *this; }

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  • OpenGL particle system

    - by allan
    I'm really new with OpenGL, so bear with me. I'm trying to simulate a particle system using OpenGl but I can't get it to work, this is what I have so far: #include <GL/glut.h> int main (int argc, char **argv){ // data allocation, various non opengl stuff ............ glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE ); glutInitWindowPosition(100,100); glutInitWindowSize(size, size); glPointSize (4); glutCreateWindow("test gl"); ............ // initial state, not opengl ............ glViewport(0,0,size,size); glutDisplayFunc(display); glutIdleFunc(compute); glutMainLoop(); } void compute (void) { // change state not opengl glutPostRedisplay(); } void display (void) { glClear(GL_COLOR_BUFFER_BIT); glBegin(GL_POINTS); for(i = 0; i<nparticles; i++) { // two types of particles if (TYPE(particle[i]) == 1) glColor3f(1,0,0); else glColor3f(0,0,1); glVertex2f(X(particle[i]),Y(particle[i])); } glEnd(); glFlush(); glutSwapBuffers(); } I get a black window after a couple of seconds (the window has just the title bar before that). Where do I go wrong? Any help would be very much appreciated. Thanks. LE: the x and y coordinates of each particle are within the interval (0,size)

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  • Better way of looping to detect change.

    - by Dremation
    As of now I'm using a while(true) method to detect changes in memory. The problem with this is it's kill the applications performance. I have a list of 30 pointers that need checked as rapidly as possible for changes, without sacrificing a huge performance loss. Anyone have ideas on this? memScan = new Thread(ScanMem); public static void ScanMem() { int i = addy.Length; while (true) { Thread.Sleep(30000); //I do this to cut down on cpu usage for (int j = 0; j < i; j++) { string[] values = addy[j].Split(new char[] { Convert.ToChar(",") }); //MessageBox.Show(values[2]); try { if (Memory.Scanner.getIntFromMem(hwnd, (IntPtr)Convert.ToInt32(values[0], 16), 32).ToString() != values[1].ToString()) { //Ok, it changed lets do our work //work if (Globals.Working) return; SomeFunction("Results: " + values[2].ToString(), "Memory"); Globals.Working = true; }//end if }//end try catch { } }//end for }//end while }//end void

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  • How to make gcc on SUN calculate floating points the same way as in Linux

    - by Marina
    I have a project where I have to perform some mathematics calculations with double variables. The problem is that I get different results on SUN Solaris 9 and Linux. There are a lot of ways (explained here and other forums) how to make Linux work as Sun, but not the other way around. I cannot touch the Linux code, so it is only SUN I can change. Is there any way to make SUN to behave as Linux? The code I run(compile with gcc on both systems): int hash_func(char *long_id) { double product, lnum, gold; while (*long_id) lnum = lnum * 10.0 + (*long_id++ - '0'); printf("lnum => %20.20f\n", lnum); lnum = lnum * 10.0E-8; printf("lnum => %20.20f\n", lnum); gold = 0.6125423371582974; product = lnum * gold; printf("product => %20.20f\n", product); ... } if the input is 339886769243483 the output in Linux: lnum => 339886769243**483**.00000000000000000000 lnum => 33988676.9243**4829473495483398** product => 20819503.600158**59827399253845** When on SUN: lnum => 339886769243483.00000000000000000000 lnum => 33988676.92434830218553543091 product = 20819503.600158**60199928283691** Note: The result is not always different, moreover most of the times it is the same. Just 10 15-digit numbers out of 60000 have this problem. Please help!!!

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  • Why this Either-monad code does not type check?

    - by pf_miles
    instance Monad (Either a) where return = Left fail = Right Left x >>= f = f x Right x >>= _ = Right x this code frag in 'baby.hs' caused the horrible compilation error: Prelude> :l baby [1 of 1] Compiling Main ( baby.hs, interpreted ) baby.hs:2:18: Couldn't match expected type `a1' against inferred type `a' `a1' is a rigid type variable bound by the type signature for `return' at <no location info> `a' is a rigid type variable bound by the instance declaration at baby.hs:1:23 In the expression: Left In the definition of `return': return = Left In the instance declaration for `Monad (Either a)' baby.hs:3:16: Couldn't match expected type `[Char]' against inferred type `a1' `a1' is a rigid type variable bound by the type signature for `fail' at <no location info> Expected type: String Inferred type: a1 In the expression: Right In the definition of `fail': fail = Right baby.hs:4:26: Couldn't match expected type `a1' against inferred type `a' `a1' is a rigid type variable bound by the type signature for `>>=' at <no location info> `a' is a rigid type variable bound by the instance declaration at baby.hs:1:23 In the first argument of `f', namely `x' In the expression: f x In the definition of `>>=': Left x >>= f = f x baby.hs:5:31: Couldn't match expected type `b' against inferred type `a' `b' is a rigid type variable bound by the type signature for `>>=' at <no location info> `a' is a rigid type variable bound by the instance declaration at baby.hs:1:23 In the first argument of `Right', namely `x' In the expression: Right x In the definition of `>>=': Right x >>= _ = Right x Failed, modules loaded: none. why this happen? and how could I make this code compile ? thanks for any help~

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  • how do I insert an hidden token in my form to prevent double posts? (PHP)

    - by jpjp
    I want to prevent users from accidentally posting a comment twice. I use the PRG (post redirect get) method, so that I insert the data on another page then redirect the user back to the page which shows the comment. This allows users to refresh as many times as they want. However this doesn't work when the user goes back and clicks submit again or when they click submit 100 times really fast. I don't want 100 of the same comments. I looked at related questions on SO and found that a token is best. But I am having trouble using it. //makerandomtoken(20) returns a random 20 length char. <form method="post" ... > <input type="text" id="comments" name="comments" class="commentbox" /><br/> <input type="hidden" name="_token" value="<?php echo $token=makerandomtoken(20); ?>" /> <input type="submit" value="submit" name="submit" /> </form> if (isset($_POST['submit']) && !empty($comments)) { $comments= mysqli_real_escape_string($dbc,trim($_POST['comments'])); //how do I make the if-statment to check if the token has been already set once? if ( ____________){ //don't insert comment because already clicked submit } else{ //insert the comment into the database } } So I have the token as a hidden value, but how do I use that to prevent multiple clicking of submit.

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  • Pointer Implementation Details in C

    - by Will Bickford
    I would like to know architectures which violate the assumptions I've listed below. Also I would like to know if any of the assumptions are false for all architectures (i.e. if any of them are just completely wrong). sizeof(int *) == sizeof(char *) == sizeof(void *) == sizeof(func_ptr *) The in-memory representation of all pointers for a given architecture is the same regardless of the data type pointed to. The in-memory representation of a pointer is the same as an integer of the same bit length as the architecture. Multiplication and division of pointer data types are only forbidden by the compiler. NOTE: Yes I know this is nonsensical. What I mean is - is there hardware support to forbid this incorrect usage? All pointer values can be casted to a single integer. In other words, what architectures still make use of segments and offsets? Incrementing a pointer is equivalent to adding sizeof(the pointed data type) to the memory address stored by the pointer. If p is an int32* then p+1 is equal to the memory address 4 bytes after p. I'm most used to pointers being used in a contiguous, virtual memory space. For that usage, I can generally get by thinking of them as addresses on a number line. See (http://stackoverflow.com/questions/1350471/pointer-comparison/1350488#1350488).

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  • Optimizing C# code in MVC controller

    - by cc0
    I am making a number of distinct controllers, one relating to each stored procedure in a database. These are only used to read data and making them available in JSON format for javascripts. My code so far looks like this, and I'm wondering if I have missed any opportunities to re-use code, maybe make some help classes. I have way too little experience doing OOP, so any help and suggestions here would be really appreciated. Here is my generalized code so far (tested and works); using System; using System.Configuration; using System.Web.Mvc; using System.Data; using System.Text; using System.Data.SqlClient; using Prototype.Models; namespace Prototype.Controllers { public class NameOfStoredProcedureController : Controller { char[] lastComma = { ',' }; String oldChar = "\""; String newChar = "&quot;"; StringBuilder json = new StringBuilder(); private String strCon = ConfigurationManager.ConnectionStrings["SomeConnectionString"].ConnectionString; private SqlConnection con; public StoredProcedureController() { con = new SqlConnection(strCon); } public string do_NameOfStoredProcedure(int parameter) { con.Open(); using (SqlCommand cmd = new SqlCommand("NameOfStoredProcedure", con)) { cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.AddWithValue("@parameter", parameter); using (SqlDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { json.AppendFormat("[{0},\"{1}\"],", reader["column1"], reader["column2"]); } } con.Close(); } if (json.Length.ToString().Equals("0")) { return "[]"; } else { return "[" + json.ToString().TrimEnd(lastComma) + "]"; } } //http://host.com/NameOfStoredProcedure?parameter=value public ActionResult Index(int parameter) { return new ContentResult { ContentType = "application/json", Content = do_NameOfStoredProcedure(parameter) }; } } }

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  • how can exec change the behavior of exec'ed program

    - by R Samuel Klatchko
    I am trying to track down a very odd crash. What is so odd about it is a workaround that someone discovered and which I cannot explain. The workaround is this small program which I'll refer to as 'runner': #include <stdio.h> #include <unistd.h> #include <string.h> #include <errno.h> int main(int argc, char *argv[]) { if (argc == 1) { fprintf(stderr, "Usage: %s prog [args ...]\n", argv[0]); return 1; } execvp(argv[1], argv + 1); fprintf(stderr, "execv failed: %s\n", strerror(errno)); // If exec returns because the program is not found or we // don't have the appropriate permission return 255; } As you can see, all this program does is use execvp to replace itself with a different program. The program crashes when it is directly invoked from the command line: /path/to/prog args # this crashes but works fine when it is indirectly invoked via my runner shim: /path/to/runner /path/to/prog args # works successfully For the life of me, I can figure out how having an extra exec can change the behavior of the program being run (as you can see the program does not change the environment). Some background on the crash. The crash itself is happening in the C++ runtime. Specifically, when the program does a throw, the crashing version incorrectly thinks there is no matching catch (although there is) and calls terminate. When I invoke the program via runner, the exception is properly caught. My question is any idea why the extra exec changes the behavior of the exec'ed program?

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  • Why is this exception thrown in the visual studio C compiler?

    - by Shane Larson
    Hello. I am trying to get more adept and my C programming and I was attempting to test out displaying a character from the input stream while inside of the loop that is getting the character. I am using the getchar() method. I am getting an exception thrown at the time that the printf statement in my code is present. (If I comment out the printf line in this function, the exception is not thrown). Exception: Unhandled exception at 0x611c91ad (msvcr90d.dll) in firstOS.exe: 0xC0000005: Access violation reading location 0x00002573. Here is the code... Any thoughts? Thank you. PS. I am using the stdio.h library. /*getCommandPromptNew - obtains a string command prompt.*/ void getCommandPromptNew(char s[], int lim){ int i, c; for(i=0; i < lim-1 && (c=getchar())!=EOF && c!='\n'; ++i){ s[i] = c; printf('%s', c); } }

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