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  • MySQLi Wrapper -- will this slow down performance?

    - by Kerry
    I found the following code on php.net. I'm trying to write a wrapper for the MySQLi library to make things incredibly simple. If this is going to slow down performance, I'll skip it and find another way, if this works, then I'll do that. I have a single query function, if someone passes in more than one variable, I assume the function has to be prepared. The function that I would use to pass in an array to mysqli_stmt_bind_param is call_user_func_array, I have a feeling that is going to slow things down. Am I right? <?php /* just explaining how to call mysqli_stmt_bind_param with a parameter array */ $sql_link = mysqli_connect('localhost', 'my_user', 'my_password', 'world'); $type = "isssi"; $param = array("5", "File Description", "File Title", "Original Name", time()); $sql = "INSERT INTO file_detail (file_id, file_description, file_title, file_original_name, file_upload_date) VALUES (?, ?, ?, ?, ?)"; $sql_stmt = mysqli_prepare ($sql_link, $sql); call_user_func_array('mysqli_stmt_bind_param', array_merge (array($sql_stmt, $type), $param); mysqli_stmt_execute($sql_stmt); ?>

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  • How to draw histogram in Processing

    - by theolc
    I have an arrayList and I would like to take the size of the ten arrayList elements and use the sizes to create a histogram. I understand processing coordinate system starts in the top left corner. My question is, how do I use the arrayList.size() values to start at 450 (based from a 500,500 window) and go upwards from there to create my histogram. The following is my function for the histogram, it is receiving as a parameter the arrayList called bins. void histogram(ArrayList[] bins) { //set window background(0,0,0); size(500,500); background(255,255,255); line(50,0,50,500); line(0,450,500,450); int i; for (i = 50; i <= 500; i+=45) { line(i,450,i,480); } for (i = 50; i <= 450; i+=45) { line(50,i,20,i); } } Thanks in adavance for any help and input!

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  • Best method to cache objects in PHP?

    - by Martin Bean
    Hi, I'm currently developing a large site that handles user registrations. A social networking website for argument's sake. However, I've noticed a lag in page loads and deciphered that it is the creation of objects on pages that's slowing things down. For example, I have a Member object, that when instantiated with an ID passed as a construct parameter, it queries the database for that members' row in the members database table. Not bad, but this is created each time a page is loaded; and called more than once when say, calling an array of that particular members' friends, as a new Member object is created for each friend. So on a single page I can have upwards of seven of the same object, but containing different properties. What I'm wanting to do is to find a way to reduce the database load, and to allow persist objects between page loads. For example, the logged in user's object to be created on login (which I can do) but then stored somewhere for retrieval so I don't have to keep re-creating the object between page loads. What is the best solution for this? I've had a look at Memcache, but with it being a third-party module I can't have the web host install it on this occasion. What are my alternatives, and/or best practices in my case? Thanks in advance.

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  • Define a positive number to be isolated if none of the digits in its square are in its cube [closed]

    - by proglaxmi
    Define a positive number to be isolated if none of the digits in its square are in its cube. For example 163 is n isolated number because 69*69 = 26569 and 69*69*69 = 4330747 and the square does not contain any of the digits 0, 3, 4 and 7 which are the digits used in the cube. On the other hand 162 is not an isolated number because 162*162=26244 and 162*162*162 = 4251528 and the digits 2 and 4 which appear in the square are also in the cube. Write a function named isIsolated that returns 1 if its argument is an isolated number, it returns 0 if its not an isolated number and it returns -1 if it cannot determine whether it is isolated or not (see the note below). The function signature is: int isIsolated(long n) Note that the type of the input parameter is long. The maximum positive number that can be represented as a long is 63 bits long. This allows us to test numbers up to 2,097,151 because the cube of 2,097,151 can be represented as a long. However, the cube of 2,097,152 requires more than 63 bits to represent it and hence cannot be computed without extra effort. Therefore, your function should test if n is larger than 2,097,151 and return -1 if it is. If n is less than 1 your function should also return -1. Hint: n % 10 is the rightmost digit of n, n = n/10 shifts the digits of n one place to the right. The first 10 isolated numbers are N n*n n*n*n 2 4 8 3 9 27 8 64 512 9 81 729 14 196 2744 24 576 13824 28 784 21952 34 1156 39304 58 3364 195112 63 3969 250047

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  • FileInput Help/Advice

    - by user559142
    I have a fileinput class. It has a string parameter in the constructor to load the filename supplied. However it just exits if the file doesn't exist. I would like it to output a message if the file doesn't exist - but not sure how.... Here is the class: public class FileInput extends Input { /** * Construct <code>FileInput</code> object given a file name. */ public FileInput(final String fileName) { try { scanner = new Scanner(new FileInputStream(fileName)); } catch (FileNotFoundException e) { System.err.println("File " + fileName + " could not be found."); System.exit(1); } } /** * Construct <code>FileInput</code> object given a file name. */ public FileInput(final FileInputStream fileStream) { super(fileStream); } } And its implementation: private void loadFamilyTree() { out.print("Enter file name: "); String fileName = in.nextLine(); FileInput input = new FileInput(fileName); family.load(input); input.close(); }

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  • JQuery 1.3.1 doesn't find dynamically generated rows

    - by Bamelis Steve
    I have just installed in the ASP.NET MVC RC2 and with that also using the JQuery 1.3.1 library. Before I was using the 1.2.6 library. Our application works fine under that library. But now I have strange problem. We have a grid view that we build up with the result of an AJAX call. With the result returned we add new rows to a table through cloning a hidden row. The generated HTML from the JQuery is placing extra parameters to the tags. These are in the form of JQuery12345678="null". They all have the same name. In the head of the table there is a checkbox that selects/unselects all the rows of the table. This by iterating through the rows of the table. $("#selectAllCheckbox").click(function() { var checked = this.checked; $("#dgNewTasks tbody tr").find(':input[type="checkbox"]').each(function() { this.checked = checked; }); }); Now by using the new library the check box are no longer set. I have used IE Developer Tools to check the HTML. If I remove the JQuery12345678="null" parameter from my rows. It works fine. Could someone tell me what I have to do?

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  • Google Chrome && (cache || memory leaks).

    - by Alexey Ogarkov
    Hello All, I have a big problem with Google Chrome and its memory. My app is displaying to user several image charts and reloads them every 10s. In the interval i have code like that var image = new Image(); var src = 'myurl/image'+new Date().getTime(); image.onload = function() { document.getElementById('myimage').src = src; image.onload = image.onabort = image.onerror = null; } image.src = src; So i have no memory leaks in Firefox and IE. Here the response headers for images Server Apache-Coyote/1.1 Vary * Cache-Control no-store (// I try no-cache, must-revalidate and so on here) Content-Type image/png Content-Length 11131 Date Mon, 31 May 2010 14:00:28 GMT Vary * taken from here In about:cache page there is no my cached images. If i enable purge-memory-button for chrome (--purge-memory-button parameter) it`s not help. Images is in PNG24. So i think that the problem is not in cache. May be Google Chrome is not releasing memory for old images. Please help. Any suggestions. Thanks.

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  • Twitter API PHP script error

    - by bardockyo
    I am having issues with my php script that I am using for gathering a users followers by accessing the twitter API. The script works fine for a user that has < 5000 followers but I tried adjusting the script using cursors to collect the complete set of users. Here is my script: <?php $cursor = -1; $file = fopen ('ids.csv', 'w+'); fwrite($file, "User id\n\r"); for ($i = 0; $i <= 1; $i++) { $xml = getFollowers($cursor); foreach ($xml->ids->id as $id) { fwrite($file, $id . ", "); fwrite($file, "\n"); } $cursor = $xml->next_cursor; } function getFollowers ($cursor) { $xmldata = 'https://api.twitter.com/1/followers/ids.xml?cursor='.$cursor.'&screen_name=microsoft'; $open = fopen($xmldata, 'r'); $content = stream_get_contents($open); fclose($open); $xml = simplexml_load_file($xmldata); return $xml; } ?> I am getting an error Warning: fopen("https://api.twitter.com/1/followers/ids.xml?cursor=-1&screen_name=microsoft") failed to open stream HTTP request failed bad request warning: stream_get_contents() expects parameter 1 to be resource, boolean given. Any ideas?

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  • Generic factory of generic containers

    - by Feuermurmel
    I have a generic abstract class Factory<T> with a method createBoxedInstance() which returns instances of T created by implementations of createInstance() wrapped in the generic container Box<T>. abstract class Factory<T> { abstract T createInstance(); public final Box<T> createBoxedInstance() { return new Box<T>(createInstance()); } public final class Box<T> { public final T content; public Box(T content) { this.content = content; } } } At some points I need a container of type Box<S> where S is an ancestor of T. Is it possible to make createBoxedInstance() itself generic so that it will return instances of Box<S> where S is chosen by the caller? Sadly, defining the function as follows does not work as a type parameter cannot be declared using the super keyword, only used. public final <S super T> Box<S> createBoxedInstance() { return new Box<S>(createInstance()); } The only alternative I see, is to make all places that need an instance of Box<S> accept Box<? extends S> which makes the container's content member assignable to S. Is there some way around this without re-boxing the instances of T into containers of type Box<S>? (I know I could just cast the Box<T> to a Box<S> but I would feel very, very guilty.)

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  • WIN32 API question - Looking for answer asap

    - by Lalit_M
    We have developed a ASP.NET web application and has implemented a custom authentication solution using active directory as the credentials store. Our front end application uses a normal login form to capture the user name and password and leverages the Win32 LogonUser method to authenticate the user’s credentials. When we are calling the LogonUser method, we are using the LOGON32_LOGON_NETWORK as the logon type. The issue we have found is that user profile folders are being created under the C:\Users folder of the web server. The folder seems to be created when a new user who has never logged on before is logging in for the first time. As the number of new users logging into the application grows, disk space is shrinking due to the large number of new user folders getting created. Has anyone seen this behavior with the Win32 LogonUser method? Does anyone know how to disable this behavior? I have tried LOGON32_LOGON_BATCH but it was giving an error 1385 in authentication user. I need either of the solution 1) Is there any way to stop the folder generation. 2) What parameter I need to pass this to work? Thanks

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  • [Scala] Using overloaded, typed methods on a collection

    - by stephanos
    I'm quite new to Scala and struggling with the following: I have database objects (type of BaseDoc) and value objects (type of BaseVO). Now there are multiple convert methods (all called 'convert') that take an instance of an object and convert it to the other type accordingly. For example: def convert(doc: ClickDoc): ClickVO = doc match { case null => null case _ => val result = new ClickVO result.x = doc.x result.y = doc.y result } Now I sometimes need to convert a list of objects. How would I do this - I tried: def convert[D <: MyBaseDoc, V <: BaseVO](docs: List[D]):List[V] = docs match { case List() => List() case xs => xs.map(doc => convert(doc)) } Which results in 'overloaded method value convert with alternatives ...'. I tried to add manifest information to it, but couldn't make it work. I couldn't even create one method for each because it'd say that they have the same parameter type after type erasure (List). Ideas welcome!

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  • null reference problems with c#

    - by alex
    Hi: In one of my window form, I created an instance of a class to do some works in the background. I wanted to capture the debug messages in that class and displayed in the textbox in the window form. Here is what I did: class A //window form class { public void startBackGroundTask() { B backGroundTask = new B(this); } public void updateTextBox(string data) { if (data != null) { if (this.Textbox.InvokeRequired) { appendUIDelegate updateDelegate = new appendUIDelegate(updateUI); try { this.Invoke(updateDelegate, data); } catch (Exception e) { Console.WriteLine(e.Message); } } else { updateUI(data); } } } private void updateUI(string data) { if (this.Textbox.InvokeRequired) { this.Textbox.Invoke(new appendUIDelegate(this.updateUI), data); } else { //update the text box this.Textbox.AppendText(data); this.Textbox.AppendText(Environment.NewLine); } } private delegate void appendUIDelegate(string data); } class B // background task { A curUI; public b( A UI) { curUI = UI; } private void test() { //do some works here then log the debug message to UI. curUI.updateTextBox("message); } } I keep getting a null reference exception after this.Invoke(updateDelegate, data); is called. I know passing "this" as a parameter is strange. But I want to send the debug message to my window form. Please help. Thanks

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  • How to get java singleton object manager to return any type of object?

    - by Robert
    I'm writing an interactive fiction game in java from scratch. I'm currently storing all of my game object references in a hashmap in a singleton called ObjectManager. ObjectManager has a function called get which takes an integer ID and returns the appropriate reference. The problem is that it returns a BaseObject when I need to return subclasses of BaseObject with more functionality. So, what I've done so far is I've added a getEntity function which returns BaseEntity (which is a subclass of BaseObject). However, when I need the function to return to an object that is a subclass of BaseEntity that has added, required functionality, I will need to make another function. I know there is a better way, but I don't know what it is. I know very little of design patterns, and I'm not sure which one to use here. I tried passing 'class' as a parameter, but that didn't get me anywhere. public BaseObject get(int ID){ return (BaseObject)refMap.get(ID); } public BaseEntity getEntity(int ID){ return (BaseEntity)refMap.get(ID); } Thanks, java ninjas!

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  • for loop vs std::for_each with lambda

    - by Andrey
    Let's consider a template function written in C++11 which iterates over a container. Please exclude from consideration the range loop syntax because it is not yet supported by the compiler I'm working with. template <typename Container> void DoSomething(const Container& i_container) { // Option #1 for (auto it = std::begin(i_container); it != std::end(i_container); ++it) { // do something with *it } // Option #2 std::for_each(std::begin(i_container), std::end(i_container), [] (typename Container::const_reference element) { // do something with element }); } What are pros/cons of for loop vs std::for_each in terms of: a) performance? (I don't expect any difference) b) readability and maintainability? Here I see many disadvantages of for_each. It wouldn't accept a c-style array while the loop would. The declaration of the lambda formal parameter is so verbose, not possible to use auto there. It is not possible to break out of for_each. In pre- C++11 days arguments against for were a need of specifying the type for the iterator (doesn't hold any more) and an easy possibility of mistyping the loop condition (I've never done such mistake in 10 years). As a conclusion, my thoughts about for_each contradict the common opinion. What am I missing here?

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  • Assigning a 2D array (of pointers) to a variable in an object for access in C++?

    - by MrMormon
    I'm sorry if I didn't pick a descriptive or concise name. A lot of questions sound similar, but I haven't been able to find what I'm looking for. What I want to do is store a 2D array of pointers somewhere and assign a variable in some object to that array to be able to access it. Here's some example code that has the same compile error I'm getting with a bigger project. #include <iostream> using namespace std; struct X{ float * b[8][8]; X(){ *(b[1][5]) = 1; cout << *(b[1][5]) << endl; } void Set(float * c[8][8]){ b = c; cout << *(b[1][5]) << endl; } }; main(){ float * a[8][8]; *(a[1][5]) = 2; X obj; obj.Set(a); } What I want to happen in this code is that an X object starts with its own 2D array, whose value pointed to by b[1][5] should be printed as "1". Then the main method's 2D array, a, is passed to the object's Set() method and assigned to its array variable. The value pointed to by b[1][5] should then be printed as "2". However, I can't figure out what type the Set() parameter, c, should be. I get error: incompatible types in assignment of ‘float* (*)[8]’ to ‘float* [8][8]’ when I try to compile. As for why I want to do this, I'm trying to use an array of pointers to objects, not floats, but it's the same error.

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  • Null pointer to struct which has zero size (empty)... It is a good practice?

    - by ProgramWriter
    Hi2All.. I have some null struct, for example: struct null_type { NullType& someNonVirtualMethod() { return *this; } }; And in some function i need to pass reference to this type. Reason: template <typename T1 = null_type, typename T2 = null_type, ... > class LooksLikeATupleButItsNotATuple { public: LooksLikeATupleButItsNotATuple(T1& ref1 = defParamHere, T2& ref2 = andHere..) : _ref1(ref1), _ref2(ref2), ... { } void someCompositeFunctionHere() { _ref1.someNonVirtualMethod(); _ref2.someNonVirtualMethod(); ... } private: T1& _ref1; T2& _ref2; ...; }; It is a good practice to use null reference as a default parameter?: *static_cast<NullType*>(0) It works on MSVC, but i have some doubts...

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  • Template Syntax in C++

    - by Crystal
    I don't understand templates really and was trying to run a simple find the minimum for ints, doubles, chars. First question, why is template<typename T> sometimes used, and other times template<>? Second question, I do not know what I am doing wrong with the following code below: #include <iostream> template <typename T> T minimum(T arg1, T arg2) { return arg1 < arg2 ? arg1 : arg2; } template <typename T> // first I tried template <> instd of above, but wasn't sure the difference T minimum<const char *>(const char *arg1, const char *arg2) { return strcmp(arg1, arg2) ? arg2 : arg1; } int main() { std::cout << minimum<int>(4, 2) << '\n'; std::cout << minimum<double>(2.2, -56.7) << '\n'; std::cout << minimum(2.2, 2) << '\n'; } Compile Errors: error C2768: 'minimum' : illegal use of explicit template arguments error C2783: 'T minimum(const char *,const char *)' : could not deduce template argument for 'T' : see declaration of 'minimum' : error C2782: 'T minimum(T,T)' : template parameter 'T' is ambiguous : see declaration of 'minimum' Third, in getting familiar with separating .h and .cpp files, if I wanted this minimum() function to be a static function of my class, but it was the only function in that class, would I have to have a template class as well? I originally tried doing it that way instead of having it all in one file and I got some compile errors as well that I can't remember right now and was unsure how I would do that. Thanks!

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  • Problem with mysql_query() ;Says resource expected .

    - by user364651
    I have this php file. The lines marked as bold are showing up the error :"mysql_query() expecets parameter 2 to be a resources. Well, the similar syntax on the line on which I have commented 'No error??' is working just fine. function checkAnswer($answerEntered,$quesId) { //This functions checks whether answer to question having ques_id = $quesId is satisfied by $answerEntered or not $sql2="SELECT keywords FROM quiz1 WHERE ques_id=$quesId"; **$result2=mysql_query($sql2,$conn);** $keywords=explode(mysql_result($result2,0)); $matches=false; foreach($keywords as $currentKeyword) { if(strcasecmp($currentKeyword,$answerEntered)==0) { $matches=true; } } return $matches; } $sql="SELECT answers FROM user_info WHERE user_id = $_SESSION[user_id]"; $result=mysql_query($sql,$conn); // No error?? $answerText=mysql_result($result,0); //Retrieve answers entered by the user $answerText=str_replace('<','',$answerText); $answerText=str_replace('>',',',$answerText); $answerText=substr($answerText,0,(strlen($answerText)-1)); $answers=explode(",",$answerText); //Get the questions that have been assigned to the user. $sql1="SELECT questions FROM user_info WHERE user_id = $_SESSION[user_id]"; **$result1=mysql_query($sql1,$conn);** $quesIdList=mysql_result($result1,0); $quesIdList=substr($quesIdList,0,(strlen($quesIdList)-1)); $quesIdArray=explode(",",$quesIdList); $reportCard=""; $i=0; foreach($quesIdArray as $currentQuesId) { $answerEnteredByUser=$answers[$i]; if(checkAnswer($answerEnteredByUser,$currentQuesId)) { $reportCard=$reportCard+"1"; } else { $reportCard=$reportCard+"0"; } $i++; } echo $reportCard; ?> Here is the file connect.php. It is working just fine for other PHP documents. <?php $conn= mysql_connect("localhost","root","password"); mysql_select_db("quiz",$conn); ?>

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  • Trying to overload + operator

    - by FrostyStraw
    I cannot for the life of me understand why this is not working. I am so confused. I have a class Person which has a data member age, and I just want to add two people so that it adds the ages. I don't know why this is so hard, but I'm looking for examples and I feel like everyone does something different, and for some reason NONE of them work. Sometimes the examples I see have two parameters, sometimes they only have one, sometimes the parameters are references to the object, sometimes they're not, sometimes they return an int, sometimes they return a Person object. Like..what is the most normal way to do it? class Person { public: int age; //std::string haircolor = "brown"; //std::string ID = "23432598"; Person(): age(19) {} Person operator+(Person&) { } }; Person operator+(Person &obj1, Person &obj2){ Person sum = obj1; sum += obj2; return sum; } I really feel like overloading a + operator should seriously be the easiest thing in the world except I DON'T KNOW WHAT I AM DOING. I don't know if I'm supposed to create the overload function inside the class, outside, if it makes a difference, why if I do it inside it only allows one parameter, I just honestly don't get it.

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  • int foo(type& bar); is a bad practice?

    - by Earlz
    Well, here we are. Yet another proposed practice that my C++ book has an opinion on. It says "a returning-value(non-void) function should not take reference types as a parameter." So basically if you were to implement a function like this: int read_file(int& into){ ... } and used the integer return value as some sort of error indicator (ignoring the fact that we have exceptions) then that function would be poorly written and it should actually be like void read_file(int& into, int& error){ } Now to me, the first one is much clearer and nice to use. If you want to ignore the error value, you do so with ease. But this book suggests the later. Note that this book does not say returning value functions are bad. It rather says that you should either only return a value or you should only use references. What are your thoughts on this? Is my book full of crap? (again)

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  • Warning: Trim expects

    - by user1257518
    I'm getting this warning Warning: trim() expects parameter 1 to be string, array given in .. which is my trim line. The full code is functioned to send an error when fields are empty. However, this error appears saying every field is empty, but only the 'native' field is meant to be required so thats my 2nd problem. Thanks for any help! session_start(); $err = array(); $user_id = intval($_SESSION['user_id']); // otherwise if (isset($_POST['doLanguage'])) { $link = mysql_connect(DB_HOST, DB_USER, DB_PASS) or die("Couldn't make connection."); // check if current user is banned $the_query = sprintf("SELECT COUNT(*) FROM users WHERE `banned` = '0' AND `id` = '%d'", $user_id); $result = mysql_query($the_query, $link); $user_check = mysql_num_rows($result); // user is ok if ($user_check > 0) { // check for empty fields foreach ($_POST as $key => $val) { $value = trim($val); if (empty($value)) { $err[] = "ERROR - $key is required"; } } // no errors if(empty($err)) { for($i = 0; $i < count($_POST["other"]); $i++) $native = mysql_real_escape_string($_POST['native'][$i]); $other = mysql_real_escape_string($_POST['other'][$i]); $other_list = mysql_real_escape_string($_POST['other_list'][$i]); $other_read = mysql_real_escape_string($_POST['other_read'][$i]); $other_spokint = mysql_real_escape_string($_POST['other_spokint'][$i]); $other_spokprod = mysql_real_escape_string($_POST['other_spokprod'][$i]); $other_writ = mysql_real_escape_string($_POST['other_writ'][$i]); // insert into the database $the_query = sprintf("INSERT INTO `language` (`user_id`,`native`,`other`,`other_list`,`other_read`, `other_spokint` ,`other_spokprod`,`other_writ` ) VALUES ('%d','%s','%s','%s','%s','%s','%s','%s')", $user_id,$native,$other,$other_list,$other_read, $other_spokint,$other_spokprod,$other_writ); // query is ok? if (mysql_query($the_query, $link) ){ // redirect to user profile header('Location: myaccount.php?id=' . $user_id); } } } }

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  • How to create a datastore.Text object out of an array of dynamically created Strings?

    - by Adrogans
    I am creating a Google App Engine server for a project where I receive a large quantity of data via an HTTP POST request. The data is separated into lines, with 200 characters per line. The number of lines can go into the hundreds, so 10's of thousands of characters total. What I want to do is concatenate all of those lines into a single Text object, since Strings have a maximum length of 500 characters but the Text object can be as large as 1MB. Here is what I thought of so far: public void doPost(HttpServletRequest req, HttpServletResponse resp) { ... String[] audioSampleData = new String[numberOfLines]; for (int i = 0; i < numberOfLines; i++) { audioSampleData[i] = req.getReader().readLine(); } com.google.appengine.api.datastore.Text textAudioSampleData = new Text(audioSampleData[0] + audioSampleData[1] + ...); ... } But as you can see, I don't know how to do this without knowing the number of lines before-hand. Is there a way for me to iterate through the String indexes within the Text constructor? I can't seem to find anything on that. Of note is that the Text object can't be modified after being created, and it must have a String as parameter for the constructor. (Documentation here) Is there any way to this? I need all of the data in the String array in one Text object. Many Thanks!

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  • Template function overloading with identical signatures, why does this work?

    - by user1843978
    Minimal program: #include <stdio.h> #include <type_traits> template<typename S, typename T> int foo(typename T::type s) { return 1; } template<typename S, typename T> int foo(S s) { return 2; } int main(int argc, char* argv[]) { int x = 3; printf("%d\n", foo<int, std::enable_if<true, int>>(x)); return 0; } output: 1 Why doesn't this give a compile error? When the template code is generated, wouldn't the functions int foo(typename T::type search) and int foo(S& search) have the same signature? If you change the template function signatures a little bit, it still works (as I would expect given the example above): template<typename S, typename T> void foo(typename T::type s) { printf("a\n"); } template<typename S, typename T> void foo(S s) { printf("b\n"); } Yet this doesn't and yet the only difference is that one has an int signature and the other is defined by the first template parameter. template<typename T> void foo(typename T::type s) { printf("a\n"); } template<typename T> void foo(int s) { printf("b\n"); } I'm using code similar to this for a project I'm working on and I'm afraid that there's a subtly to the language that I'm not understanding that will cause some undefined behavior in certain cases. I should also mention that it does compile on both Clang and in VS11 so I don't think it's just a compiler bug.

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  • php mysql_fetch_array() error

    - by user1877823
    I am getting this error while i am trying to delete a record the query is working but this line remains on the page. i want to echo "Deleted" written in the while should show up but the while loop is not working, i have tried and searched alot nothing helps! mysql_fetch_array() expects parameter 1 to be resource, boolean given in delete.php on line 27 delete.php <html> <body> <form method="post"> Id : <input type="text" name="id"> Name : <input type="text" name="name"> Description : <input type="text" name="des"> <input type="submit" value="delete" name="delete"> </form> <?php include("connect.php"); $id = $_POST['id']; $name = $_POST['name']; $des = $_POST['des']; $result = mysql_query("DELETE FROM fact WHERE id='$id'") or die(mysql_error()); while($row = mysql_fetch_array($result)) { echo "Deleted"; } mysql_close($con); ?> </body> </html> connect.php <?php $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("Dataentry", $con); ?> How should i make the while loop work..

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  • What does this Java generics paradigm do and what is it called?

    - by Tom
    I'm looking at some Java classes that have the following form: public abstract class A <E extends A<E>> implements Comparable <E> { public final int compareTo( E other ) { // etc } } public class B extends A <B> { // etc } public class C extends A <C> { // etc } My usage of "Comparable" here is just to illustrate a possible use of the generic parameter "E". Does this usage of generics/inheritance have a name? What is it used for? My impression is that this allows the abstract class to provide a common implementation of a method (such as compareTo) without having to provide it in the subclasses. However, in this example, unlike an inherited method it would restrict subclasses to invoking compareTo on other instances of the same subclass, rather than any "A" subclass. Does this sound right? Anyway, just curious if any gurus out there have seen this before and know what it does. Thanks!

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