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  • How do I convert jstring to wchar_t *

    - by Obediah Stane
    Let's say that on the C++ side my function takes a variable of type jstring named myString. I can convert it to an ANSI string as follows: const char* ansiString = env-GetStringUTFChars(myString, 0); is there a way of getting const wchar_t* unicodeString = ...

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  • Should we use temporary variables for the returned values of functions?

    - by totymedli
    I thought about this: Is there a performance difference in these two practices: Store the return value of a function in a temporary variable than give that variable as a parameter to another function. Put the function into the other function. Specification Assuming all classes and functions are written correctly. Case 1. ClassA a = function1(); ClassB b = function2(a); function3(b); Case 2. function3(function2(function1())); I know there aren't a big difference with only one run, but supposed that we could run this a lot of times in a loop, I created some tests. Test #include <iostream> #include <ctime> #include <math.h> using namespace std; int main() { clock_t start = clock(); clock_t ends = clock(); // Case 1. start = clock(); for (int i=0; i<10000000; i++) { double a = cos(1); double b = pow(a, 2); sqrt(b); } ends = clock(); cout << (double) (ends - start) / CLOCKS_PER_SEC << endl; // Case 2. start = clock(); for (int i=0; i<10000000; i++) sqrt(pow(cos(1),2)); ends = clock(); cout << (double) (ends - start) / CLOCKS_PER_SEC << endl; return 0; } Results Case 1 = 6.375 Case 2 = 0.031 Why is the first one is much slower, and if the second one is faster why dont we always write code that way? Anyway does the second pratice has a name? I also wondered what happens if I create the variables outside the for loop in the first case, but the result was the same. Why?

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  • iPhone memory management (with specific examples/questions)

    - by donkim
    Hey all. I know this question's been asked but I still don't have a clear picture of memory management in Objective-C. I feel like I have a pretty good grasp of it, but I'd still like some correct answers for the following code. I have a series of examples that I'd love for someone(s) to clarify. Setting a value for an instance variable. Say I have an NSMutableArray variable. In my class, when I initialize it, do I need to call a retain on it? Do I do fooArray = [[[NSMutableArray alloc] init] retain]; or fooArray = [[NSMutableArray alloc] init]; Does doing [[NSMutableArray alloc] init] already set the retain count to 1, so I wouldn't need to call retain on it? On the other hand, if I called a method that I know returns an autoreleased object, I would for sure have to call retain on it, right? Like so: fooString = [[NSString stringWithFormat:@"%d items", someInt] retain]; Properties. I ask about the retain because I'm a bit confused about how @property's automatic setter works. If I had set fooArray to be a @property with retain set, Objective-C will automatically create the following setter, right? - (void)setFooArray:(NSMutableArray *)anArray { [fooArray release]; fooArray = [anArray retain]; } So, if I had code like this: self.fooArray = [[NSMutableArray alloc] init]; (which I believe is valid code), Objective-C creates a setter method that calls retain on the value assigned to fooArray. In this case, will the retain count actually be 2? Correct way of setting a value of a property. I know there are questions on this and (possibly) debates, but which is the right way to set a @property? This? self.fooArray = [[NSMutableArray alloc] init]; Or this? NSMutableArray *anArray = [[NSMutableArray alloc] init]; self.fooArray = anArray; [anArray release]; I'd love to get some clarification on these examples. Thanks!

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  • dao as a member of a servlet - normal?

    - by EugeneP
    I guess, DAO is thread safe, does not use any class members. So can it be used without any problem as a private field of a Servlet ? We need only one copy, and multiple threads can access it simultaneously, so why bother creating a local variable, right?

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  • Dynamic jQuery Validate error messages with AddMethod based on the element

    - by mcpDESIGNS
    Let's say I have a custom AddMethod to jQuery Validate like: $.validator.addMethod('min-length', function (val, element) { // do stuff // the error message here needs to be dynamic }, 'The field cannot be less than than ' + element.attr('data-min') + // it is within the closure, but it can't grab it ' length.'); I can't figure out a way to get the element variable in question, and get any values from it. What am I missing here?

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  • Selecting all elements

    - by Eelke
    This should be really simple but I'm a javascript/jQuery rookie, so here we go: With the following code I can select a certain element var user = $(".ui-selected .user-name").html(); But if there are multiple elements with the above classes, only the first value gets selected. What I would like to accomplish is a variable with all the elements seperated by a , like: user1,user2,user3 ... etc. Any help would be greatly appreciated, thanks in advance!

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  • How to move value from the stack to ST(0)?

    - by George Edison
    I am having trouble believing the following code is the most efficient way to move a value from the stack to ST(0): .data var dd 4.2 tmp dd ? .code mov EAX, var push EAX ; top of stack now contains a value ; move it to ST(0) pop EAX mov tmp, EAX fld tmp Is the temporary variable really necessary? Further, is there an easier way to get a value from the stack to ST(0)?

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  • Call main() itself in c++?

    - by Mask
    int main() { cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!! system("pause"); return main(); } The above works,but it hardcoded the main(),is there a magic variable to get the current running function?

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  • xargs command works on ubuntu, but not mac

    - by Corey Hart
    I have the following line of code that I use to update my personal date variable in my projects to todays current date. This line works in Ubuntu's terminal, but the Mac terminal seems to be far behind. Unfortunately, I copied this snippet from some site, so I'm not sure how it exactly works. Suggestions? grep -ilr --exclude=revar.sh --exclude=README.md "[DATE]" * | grep -v .git | xargs -i@ sed -i "s/\[DATE\]/${today}/g" @

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  • Tracing memory leaks

    - by iFloh
    My favorite candidate again. I am in the process of identifying memory leaks in my app (a puzzling challenge for a newbe like me). I am using the xCode leak analyzer, but what puzzles me is how to trace back a memory leak to its variable or value. Is there a pointer to the instances that have reserved a memory address where a leak is identifyed? How do I best go about it?

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  • How many indexes will actually get used?

    - by Ender
    I'm writing a page that does very simple search queries, resulting in something like: SELECT * FROM my_table WHERE A in (a1, a2, a3) AND B in (b1, b2) AND C in (c1, c2, c3, c4) AND And so on for a variable number of columns, usually ~5. If I create a separate index for each column (one for A, one for B, one for C, not (A,B,C)), will all of them be used in the above query?

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  • c++ volatile multithreading variables

    - by anon
    I'm writing a C++ app. I have a class variable that more than one thread is writing to. In C++, anything that can be modified without the compiler "realizing" that it's being changed needs to be marked volatile right? So if my code is multi threaded, and one thread may write to a var while another reads from it, do I need to mark the var volaltile? [I don't have a race condition since I'm relying on writes to ints being atomic] Thanks!

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  • Batch File Wildcards

    - by thebourneid
    I want to generate a bat file for multiple tag processing and the command lines look like this: "C:\Program Files (x86)\tools\tag.exe" -t Genre="%genre%" "%_folderpath%\%track%. %title%.%_extension%" IF ERRORLEVEL==1 PAUSE I can populate all variables automatically but can I replace the %title% variable with a wildcard?

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  • == and === operators in php

    - by Lizard
    Lets say I have a variable that will always be a string. Now take the code below: if($myVar === "teststring") Note $myVar will always be a string, so my questions is Which is quicker/best, using === (Indentity) or the == (Equality)?

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  • extJs Json Reader

    - by tinti
    Please help me with this problem. I'm new in extJs and i need a little help. I have this code Ext.onReady(function() { var datesStore = new Ext.data.JsonStore({ start : 'StartTableDate', end : 'FinishTableDate', autoLoad : true, proxy : new Ext.data.HttpProxy({ url : 'dates.json', method:'GET' }), fields : [ // 2 mandatory fields {name:'StartTableDate'}, {name:'FinishTableDate'} ] }); // i want to pass to variable start si end the values from JSON var start = 'StartTableDate'; var end = 'FinishTableDate';

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  • String replacment in batch file

    - by Faisal
    We can replace strings in a batch file using the following command set str="jump over the chair" set str=%str:chair=table% These lines work fine and change the string "jump over the chair" to "jump over the table". Now I want to replace the word "chair" in the string with some variable and I don't know how to do it. set word=table set str="jump over the chair" ?? Any ideas?

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  • How to remove unwanted charecters using split in tcl

    - by Mallikarjunarao
    Here is an example Interface {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} IP-Address {} {} {} {} {} OK? Method Status {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {Protocol FastEthernet0/0} {} {} {} {} {} {} {} {} {} {} {} unassigned {} {} {} {} {} YES unset {} administratively down down {} {} {} { FastEthernet0/1} {} {} {} {} {} {} {} {} {} {} {} unassigned {} {} {} {} {} YES unset {} administratively down down I want remove {} in this. I assumed all the above string interface variable set interface [string trimright [string trimleft $interface "{}"] "{}"] but it doesn't work. How to remove the {} in my example?

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  • pagination - 10 pages per page

    - by arthur
    I have a pagination script that displays a list of all pages like so: prev [1][2][3][4][5][6][7][8][9][10][11][12][13][14] next But I would like to only show ten of the numbers at a time: prev [3][4][5][6][7][8][9][10][11][12] next How can I accomplish this? Here is my code so far: <?php /* Set current, prev and next page */ $page = (!isset($_GET['page']))? 1 : $_GET['page']; $prev = ($page - 1); $next = ($page + 1); /* Max results per page */ $max_results = 2; /* Calculate the offset */ $from = (($page * $max_results) - $max_results); /* Query the db for total results. You need to edit the sql to fit your needs */ $result = mysql_query("select title from topics"); $total_results = mysql_num_rows($result); $total_pages = ceil($total_results / $max_results); $pagination = ''; /* Create a PREV link if there is one */ if($page > 1) { $pagination .= '< a hr_ef="?page='.$prev.'">Previous</a> '; } /* Loop through the total pages */ for($i = 1; $i <= $total_pages; $i++) { if(($page) == $i) { $pagination .= $i; } else { $pagination .= '< a hr_ef="index.php?page='.$i.'">'.$i.'</a>'; } } /* Print NEXT link if there is one */ if($page < $total_pages) { $pagination .= '< a hr_ef="?page='.$next.'"> Next</a>'; } /* Now we have our pagination links in a variable($pagination) ready to print to the page. I pu it in a variable because you may want to show them at the top and bottom of the page */ /* Below is how you query the db for ONLY the results for the current page */ $result=mysql_query("select * from topics LIMIT $from, $max_results "); while ($i = mysql_fetch_array($result)) { echo $i['title'].'<br />'; } echo $pagination; ?>

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  • Cocoa: what is the var name of an instance created by a NIB file?

    - by Nibbles
    When a Cocoa NIB file instantiates an instance of a custom controller object, what is the name of the variable that that custom controller instance is assigned to? In case that isn't clear, if you manually created an instance of that class you would do: MyControllerClass *myVar = [[MyControllerClass alloc] init]; What equivalent of "myVar" has the NIB used when doing this behind the scenes?

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