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  • Objective-C : Member variable is losing reference between method calls.

    - by Winston
    Hello, I've been having with an objective-c class which appears to be losing its pointer reference between methods of the same class. In the MyTableViewController.h file, I declare: @interface SettingsTableViewController : UITableViewController <UITextFieldDelegate>{ OCRAppDelegate *delegate; } MyTableViewController.m file - (id) init { self = [ super initWithStyle: UITableViewStyleGrouped ]; delegate = [(OCRAppDelegate *)[[UIApplication sharedApplication] delegate] retain]; } The problem is when the "MyTableViewController" view appears again and a different method is executed within that same class, the delegate pointer (which was assigned during the init method) is no longer there. I tried to retain, but to no avail. Would anyone know why this is, it seems like perhaps it is a fundamental Objective-C issue which I am missing. Appreciate your help. Thanks, Winston

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  • Count query with 3 coloumn iin SQL

    - by asher baig
    I have one database Library with table named called Medien. Having multiple columns named as Fname,Mname,Lname and ISBN. I want to calculate database records with ISBN and without ISBN? I have execute following command Select COUNT(ISBN) as Verf1 FROM library.MEDIEN where verf1 = isbn; Select COUNT(ISBN) as Verf2 FROM library.MEDIEN where verf2 = isbn; Select COUNT(ISBN) as Verf3 FROM library.MEDIEN where verf3 = isbn; Select COUNT(ISBN) as Ntverf1 FROM library.MEDIENwhere verf1 != isbn; Select COUNT(ISBN) as Ntverf2 FROM library.MEDIENwhere verf2 != isbn; Select COUNT(ISBN) as Ntverf3 FROM library.MEDIENwhere verf3 != isbn; I am not sure i execute correct command or not. Because some ISBN records have Fname,Mname or Fname,Lname or Mname,Lname or Fname , Lname,Mname only respectively. Please kindly help me solving this query

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  • How to retrieve stored reference to an NSManagedObject subclass?

    - by DavidDev
    Hi! I have a NSManagedObject subclass named Tour. I stored the reference to it using this code: prefs = [NSUserDefaults standardUserDefaults]; NSURL *myURL = [[myTour objectID] URIRepresentation]; NSData *uriData = [NSKeyedArchiver archivedDataWithRootObject:myURL]; [prefs setObject:uriData forKey:@"tour"]; Now I want to retrieve it. I tried using: NSData *myData = [prefs objectForKey:@"tour"]; NSURL *myURL = [NSKeyedUnarchiver unarchiveObjectWithData:myData]; TourAppDelegate *appDelegate = (TourAppDelegate *)[[UIApplication sharedApplication] delegate]; NSManagedObjectID *myID = [appDelegate.persistentStoreCoordinator managedObjectIDForURIRepresentation:myURL]; if (myID) { Tour *tempObject = [appDelegate.managedObjectContext objectWithID:myID]; //WARNING tour = tempObject; } if (tour) //instruction... But it's giving me this warning "Incompatible Objective-c types. Initializing 'struct NSManagedObject *', expected 'struct Tour *' Plus, when executing, it's giving me this: Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault for '0x5001eb0 How can I solve this?

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  • sql query question / count

    - by scheibenkleister
    Hi, I have houses that belongs to streets. A user can buy several houses. How do I find out, if the user owns an entire street? street table with columns (id/name) house table with columns (id/street_id [foreign key] owner table with columns (id/house_id/user_id) [join table with foreign keys] So far, I'm using count which returns the result: select count(*), street_id from owner left join house on owner.house_id = house.id group by street_id where user_id = 1 count(*) | street_id 3 | 1 2 | 2 A more general count: select count(*) from house group by street_id returns: count(*) | street_id 3 | 1 3 | 2 How can I find out, that user 1 owns the entire street 1 but not street 2? Thanks.

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  • How Do I Pass The Value (Not The Reference) of a JS Variable to a Function?

    - by ryan
    Here is a simplified version of something I'm trying to run: for (var i = 0; i < results.length; i++) { marker = results[i]; google.maps.event.addListener(marker, 'click', function() { change_selection(i); }); } but I'm finding that every listener uses the value of results.length (the value when the for loop terminates). How can I add listeners such that each uses the value of i at the time I add it, rather than the reference to i?

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  • MySQL: Count occurrences of known (or enumerated) distinct values

    - by Eilidh
    After looking at how to count the occurrences of distinct values in a field, I am wondering how to count the occurrences of each distinct value if the distinct values are known (or enumerated). For example, if I have a simple table - TrafficLight Colour ------------ ------ 1 Red 2 Amber 3 Red 4 Red 5 Green 6 Green where one column (in this case Colour) has known (or enumerated) distinct values, how could I return the count for each colour as a separate value, rather than as an array, as in the linked example. To return an array with a count of each colour (using the same method as in the linked example), the query would be something like SELECT Colour COUNT(*) AS ColourCount FROM TrafficLights GROUP BY Colour, and return an array - Colour ColourCount ------ ----------- Red 3 Amber 1 Green 2 What I would like to do is to return the count for each Colour AS a separate total (e.g. RedCount). How can I do this?

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  • Mysql query: count and distinct

    - by Azevedo
    I have this hypotetical MySQL table: TABLE cars: (year, color, brand) How do I count # of cars grouped by brand and year? I mean, how can I get to know how many colors are there grouped by brand like: brand "GM": total # of colors: 8. brand "GM": total # of years (grouped together): 14 (meaning there are count of 14 different years). brand "TOYOTA": total # of colors: 3. brand "TOYOTA": total # of years (grouped together): 10 (meaning there are count of 14 different years) I tried playing some queries with COUNT, DISTINCT, GROUP BY but I can't get to it. Actually I'm trying to get the 2 queries... +-------+---------------+ | brand | count(colors) | +-------+---------------+ +-------+--------------+ | brand | count(years) | +-------+--------------+ thanks a lot!

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  • Is it possible to reinterpret pointer as dimensioned array reference?

    - by aaa
    hi. Suppose I have some pointer, which I want to reinterpret as static dimension array reference: double *p; double (&r)[4] = ?(p); // some construct? // clarify template< size_t N> void function(double (&a)[N]); ... double *p; function(p); // this will not work. // I would like to cast p as to make it appear as double[N] Is it possible to do so? how do I do it?

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  • This code appears to achieve the return of a null reference in C++

    - by Chuck
    Hi folks, My C++ knowledge is somewhat piecemeal. I was reworking some code at work. I changed a function to return a reference to a type. Inside, I look up an object based on an identifier passed in, then return a reference to the object if found. Of course I ran into the issue of what to return if I don't find the object, and in looking around the web, many people claim that returning a "null reference" in C++ is impossible. Based on this advice, I tried the trick of returning a success/fail boolean, and making the object reference an out parameter. However, I ran into the roadblock of needing to initialize the references I would pass as actual parameters, and of course there is no way to do this. I retreated to the usual approach of just returning a pointer. I asked a colleague about it. He uses the following trick quite often, which is accepted by both a recent version of the Sun compiler and by gcc: MyType& someFunc(int id) { // successful case here: // ... // fail case: return *static_cast<MyType*>(0); } // Use: ... MyType& mt = somefunc(myIdNum); if (&mt) // test for "null reference" { // whatever } ... I have been maintaining this code base for a while, but I find that I don't have as much time to look up the small details about the language as I would like. I've been digging through my reference book but the answer to this one eludes me. Now, I had a C++ course a few years ago, and therein we emphasized that in C++ everything is types, so I try to keep that in mind when thinking things through. Deconstructing the expression: "*static_cast(0);", it indeed seems to me that we take a literal zero, cast it to a pointer to MyType (which makes it a null pointer), and then apply the dereferencing operator in the context of assigning to a reference type (the return type), which should give me a reference to the same object pointed to by the pointer. This sure looks like returning a null reference to me. Any advice in explaining why this works (or why it shouldn't) would be greatly appreciated. Thanks, Chuck

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  • Return cell reference as result of if statement with vlookups.

    - by EMJ
    I have two sets of data in excel. One contains a set of data which represents the initial step of a process. The other set of data represents the additional steps which take place after the first step is completed. Each of the data records in the "additional step data" has an id in a column. I need to find the identifying codes of the "additional step data" which correspond with the initial step data records. The problem is that I have to match the data in 4 columns between the two data sets and return the id of the "additional step data". I started by doing a combination of an if and vlookup functions, but I got stuck when I tried to figure out how to get the if statement to reference the id of the matching "additional step data". Basically I am trying to avoid having to search by manually filtering between two sets of data and finding corresponding records. Does anyone have any idea about how to do this?

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  • C++ standard: dereferencing NULL pointer to get a reference?

    - by shoosh
    I'm wondering about what the C++ standard says about code like this: int* ptr = NULL; int& ref = *ptr; int* ptr2 = &ref; In practice the result is that ptr2 is NULL but I'm wondering, is this just an implementation detail or is this well defined in the standard? Under different circumstances a dereferencing of a NULL pointer should result in a crash but here I'm dereferencing it to get a reference which is implemented by the compiler as a pointer so there's really no actual dereferencing of NULL.

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  • numberOfSectionsInTable isn't called when [arr count] is returned

    - by user315471
    When I try returning the count of my newsItems array it breaks my application. I used NSLog to find out what the value of the newsItems count was when I returned 1. Here is from NSLog 2010-04-13 07:48:40.656 RSS Feed[453:207] Values of num items 31 2010-04-13 07:48:40.656 RSS Feed[453:207] Number of items 31 Does anyone know why returning [newsItems count] would cause my application to break? - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { NSLog(@"Values of num items %d",[newsItems count]); NSInteger *length = (NSInteger *)[newsItems count]; NSLog(@"Number of items %d",length); return 1; //return [newsItems count]; //This keeps breaking it for some reason }

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  • Oracle Customer Reference Forum – Apex IT – Oracle Sales Cloud

    - by Richard Lefebvre
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Apex IT, an Oracle Platinum Partner, wins Nucleus Research's ROI Award with a 724% return. Learn how you can improve your ROI with Oracle Sales and Marketing Cloud. We are pleased to invite you to a discussion with Apex IT on industry trends, why sales automation is important, the decision making process for choosing Oracle Sales Cloud, and benefits achieved since going live. Apex IT works with clients large and small, assisting them at all stages in the process: organizing ideas and developing strategies, selecting the most appropriate package, implementing it for best results, and keeping systems optimized with long-term support. Please plan to register at least three hours prior to the event taking place in order to participate and get the dial-in information associated in due time. Speakers: Bryan Hinz, Vice President of Business Development, Apex IT (Speaker) Chris Haven, Senior Director Product Management, Oracle (Moderator) Organization Profile: Since 1997, Apex IT has helped public sector, corporate and higher education clients use technology to streamline their processes and increase productivity and profitability. Based on products and best practices from Oracle our experts provide a full range of enterprise solutions including CX/CRM and related applications that support marketing, sales, and service; HR and HR Helpdesk; and Business Intelligence. Our project approach is results-driven and our attitude is people-focused. Industry: Professional Services Products/Services: Oracle Sales Cloud Organization Website: http://apexit.com/ Event Description: In this informal reference call, you will have the opportunity to hear Apex IT discuss industry trends, why sales automation is important, the decision making process for choosing Oracle Sales Cloud, and benefits achieved since going live. The call will open with a brief overview, followed by discussion, and an open question and answer session. Please allow one hour for the call. Why Oracle: Apex IT needed a mobile-enabled sales force automation tool that could promote account collaboration and integrate with Microsoft Outlook. Oracle Sales Cloud met these needs and Apex IT’s requirements for: Improved collaborative selling Improved quality of customer engagement and information Improved business development Improved pipeline management Please plan to register at least three hours prior to the event taking place in order to participate and get the dial-in information associated in due time. After you register your information will be forwarded through an Approval Process. Once your registration request has been validated against the invitation database, you will receive an email confirmation with your registration details as long as there is availability. Please be advised that Apex IT will revise the registrants list and may dismiss registrations as they see fit. Note: To access more information at the corporate site you would need an Oracle.com account. If you do not already have an account, getting one is easy and free. Click on the link and you will be prompted to create an account. After you have created your account, you will be automatically returned to the full page description of this event. Register Now! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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  • ARTS Reference Model for Retail

    - by Sanjeev Sharma
    Consider a hypothetical scenario where you have been tasked to set up retail operations for a electronic goods or daily consumables or a luxury brand etc. It is very likely you will be faced with the following questions: What are the essential business capabilities that you must have in place?  What are the essential business activities under-pinning each of the business capabilities, identified in Step 1? What are the set of steps that you need to perform to execute each of the business activities, identified in Step 2? Answers to the above will drive your investments in software and hardware to enable the core retail operations. More importantly, the choices you make in responding to the above questions will several implications in the short-run and in the long-run. In the short-term, you will incur the time and cost of defining your technology requirements, procuring the software/hardware components and getting them up and running. In the long-term, as you grow in operations organically or through M&A, partnerships and franchiser business models  you will invariably need to make more technology investments to manage the greater complexity (scale and scope) of business operations.  "As new software applications, such as time & attendance, labor scheduling, and POS transactions, just to mention a few, are introduced into the store environment, it takes a disproportionate amount of time and effort to integrate them with existing store applications. These integration projects can add up to 50 percent to the time needed to implement a new software application and contribute significantly to the cost of the overall project, particularly if a systems integrator is called in. This has been the reality that all retailers have had to live with over the last two decades. The effect of the environment has not only been to increase costs, but also to limit retailers' ability to implement change and the speed with which they can do so." (excerpt taken from here) Now, one would think a lot of retailers would have already gone through the pain of finding answers to these questions, so why re-invent the wheel? Precisely so, a major effort began almost 17 years ago in the retail industry to make it less expensive and less difficult to deploy new technology in stores and at the retail enterprise level. This effort is called the Association for Retail Technology Standards (ARTS). Without standards such as those defined by ARTS, you would very likely end up experiencing the following: Increased Time and Cost due to resource wastage arising from re-inventing the wheel i.e. re-creating vanilla processes from scratch, and incurring, otherwise avoidable, mistakes and errors by ignoring experience of others Sub-optimal Process Efficiency due to narrow, isolated view of processes thereby ignoring process inter-dependencies i.e. optimizing parts but not the whole, and resulting in lack of transparency and inter-departmental finger-pointing Embracing ARTS standards as a blue-print for establishing or managing or streamlining your retail operations can benefit you in the following ways: Improved Time-to-Market from parity with industry best-practice processes e.g. ARTS, thus avoiding “reinventing the wheel” for common retail processes and focusing more on customizing processes for differentiations, and lowering integration complexity and risk with a standardized vocabulary for exchange between internal and external i.e. partner systems Lower Operating Costs by embracing the ARTS enterprise-wide process reference model for developing and streamlining retail operations holistically instead of a narrow, silo-ed view, and  procuring IT systems in compliance with ARTS thus avoiding IT budget marginalization While parity with industry standards such as ARTS business process model by itself does not create a differentiation, it does however provide a higher starting point for bridging the strategy-execution gap in setting up and improving retail operations.

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  • MDX using EXISTING, AGGREGATE, CROSSJOIN and WHERE

    - by James Rogers
    It is a well-published approach to using the EXISTING function to decode AGGREGATE members and nested sub-query filters.  Mosha wrote a good blog on it here and a more recent one here.  The use of EXISTING in these scenarios is very useful and sometimes the only option when dealing with multi-select filters.  However, there are some limitations I have run across when using the EXISTING function against an AGGREGATE member:   The AGGREGATE member must be assigned to the Dimension.Hierarchy being detected by the EXISTING function in the calculated measure. The AGGREGATE member cannot contain a crossjoin from any other dimension or hierarchy or EXISTING will not be able to detect the members in the AGGREGATE member.   Take the following query (from Adventure Works DW 2008):   With   member [Week Count] as 'count(existing([Date].[Fiscal Weeks].[Fiscal Week].members))'    member [Date].[Fiscal Weeks].[CM] as 'AGGREGATE({[Date].[Fiscal Weeks].[Fiscal Week].&[47]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[48]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[49]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[50]&[2004]})'   select   {[Week Count]} on columns from   [Adventure Works]     where   [Date].[Fiscal Weeks].[CM]   Here we are attempting to count the existing fiscal weeks in slicer.  This is useful to get a per-week average for another member. Many applications generate queries in this manner (such as Oracle OBIEE).  This query returns the correct result of (4) weeks. Now let's put a twist in it.  What if the querying application submits the query in the following manner:   With   member [Week Count] as 'count(existing([Date].[Fiscal Weeks].[Fiscal Week].members))'    member [Customer].[Customer Geography].[CM] as 'AGGREGATE({[Date].[Fiscal Weeks].[Fiscal Week].&[47]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[48]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[49]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[50]&[2004]})'   select   {[Week Count]} on columns from   [Adventure Works]     where   [Customer].[Customer Geography].[CM]   Here we are attempting to count the existing fiscal weeks in slicer.  However, the AGGREGATE member is built on a different dimension (in name) than the one EXISTING is trying to detect.  In this case the query returns (174) which is the total number of [Date].[Fiscal Weeks].[Fiscal Week].members defined in the dimension.   Now another twist, the AGGREGATE member will be named appropriately and contain the hierarchy we are trying to detect with EXISTING but it will be cross-joined with another hierarchy:   With   member [Week Count] as 'count(existing([Date].[Fiscal Weeks].[Fiscal Week].members))'    member [Date].[Fiscal Weeks].[CM] as 'AGGREGATE({[Date].[Fiscal Weeks].[Fiscal Week].&[47]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[48]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[49]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[50]&[2004]}*    {[Customer].[Customer Geography].[Country].&[Australia],[Customer].[Customer Geography].[Country].&[United States]})'  select   {[Week Count]} on columns from   [Adventure Works]    where   [Date].[Fiscal Weeks].[CM]   Once again, we are attempting to count the existing fiscal weeks in slicer.  Again, in this case the query returns (174) which is the total number of [Date].[Fiscal Weeks].[Fiscal Week].members defined in the dimension. However, in 2008 R2 this query returns the correct result of 4 and additionally , the following will return the count of existing countries as well (2):   With   member [Week Count] as 'count(existing([Date].[Fiscal Weeks].[Fiscal Week].members))'   member [Country Count] as 'count(existing([Customer].[Customer Geography].[Country].members))'  member [Date].[Fiscal Weeks].[CM] as 'AGGREGATE({[Date].[Fiscal Weeks].[Fiscal Week].&[47]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[48]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[49]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[50]&[2004]}*    {[Customer].[Customer Geography].[Country].&[Australia],[Customer].[Customer Geography].[Country].&[United States]})'  select   {[Week Count]} on columns from   [Adventure Works]    where   [Date].[Fiscal Weeks].[CM]   2008 R2 seems to work as long as the AGGREGATE member is on at least one of the hierarchies attempting to be detected (i.e. [Date].[Fiscal Weeks] or [Customer].[Customer Geography]). If not, it seems that the engine cannot find a "point of entry" into the aggregate member and ignores it for calculated members.   One way around this would be to put the sets from the AGGREGATE member explicitly in the WHERE clause (slicer).  I realize this is only supported in SSAS 2005 and 2008.  However, after talking with Chris Webb (his blog is here and I highly recommend following his efforts and musings) it is a far more efficient way to filter/slice a query:   With   member [Week Count] as 'count(existing([Date].[Fiscal Weeks].[Fiscal Week].members))'    select   {[Week Count]} on columns from   [Adventure Works]    where   ({[Date].[Fiscal Weeks].[Fiscal Week].&[47]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[48]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[49]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[50]&[2004]}   ,{[Customer].[Customer Geography].[Country].&[Australia],[Customer].[Customer Geography].[Country].&[United States]})   This query returns the correct result of (4) weeks.  Additionally, we can count the cross-join members of the two hierarchies in the slicer:   With   member [Week Count] as 'count(existing([Date].[Fiscal Weeks].[Fiscal Week].members)*existing([Customer].[Customer Geography].[Country].members))'    select   {[Week Count]} on columns from   [Adventure Works]    where   ({[Date].[Fiscal Weeks].[Fiscal Week].&[47]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[48]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[49]&[2004],[Date].[Fiscal Weeks].[Fiscal Week].&[50]&[2004]}   ,{[Customer].[Customer Geography].[Country].&[Australia],[Customer].[Customer Geography].[Country].&[United States]})   We get the correct number of (8) here.

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  • How do I pass a const reference in C#?

    - by Maciek
    In C++, passing const references is a common practice - for instance : #include <iostream> using namespace std; class X { public : X() {m_x = 0; } X(const int & x) {m_x = x; } X(const X & other) { *this = other; } X & operator = (const X & other) { m_x = other.m_x; return *this; } void print() { cout << m_x << endl; } private : int m_x; }; void main() { X x1(5); X x2(4); X x3(x2); x2 = x1; x1.print(); x2.print(); x3.print(); } This very simple example illustrates how it's done - pretty much. However I've noticed that in C# this doesn't seem to be the case. Do I have to pass const references in C# ? what do I need the "ref" keyword for? Please note that I know and understand what C# reference and value types are.

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  • Is it okay to implement reference counting through composition?

    - by Billy ONeal
    Most common re-usable reference counted objects use private inheritance to implement re-use. I'm not a huge fan of private inheritance, and I'm curious if this is an acceptable way of handling things: class ReferenceCounter { std::size_t * referenceCount; public: ReferenceCounter() : referenceCount(NULL) {}; ReferenceCounter(ReferenceCounter& other) : referenceCount(other.referenceCount) { if (!referenceCount) { referenceCount = new std::size_t(1); other.referenceCount = referenceCount; } else { ++(*referenceCount); } }; ReferenceCounter& operator=(const ReferenceCounter& other) { ReferenceCounter temp(other); swap(temp); return *this; }; void swap(ReferenceCounter& other) { std::swap(referenceCount, other.referenceCount); }; ~ReferenceCounter() { if (referenceCount) { --(*referenceCount); if (!*referenceCount) delete referenceCount; } }; operator bool() const { return referenceCount && (*referenceCount != 0); }; }; class SomeClientClass { HANDLE someHandleThingy; ReferenceCounter objectsStillActive; public: SomeClientClass() { //Construct handle thingy } ~SomeClientClass() { if (objectsStillActive) return; //Release resources }; }; or are there subtle problems with this I'm not seeing?

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  • Please help with C++ syntax for const accessor by reference.

    - by Hamish Grubijan
    Right not my implementation returns the thing by value. The member m_MyObj itself is not const - it's value changes depending on what the user selects with a Combo Box. I am no C++ guru, but I want to do this right. If I simply stick a & in front of GetChosenSourceSystem in both decl. and impl., I get one sort of compiler error. If I do one but not another - another error. If I do return &m_MyObj;. I will not list the errors here for now, unless there is a strong demand for it. I assume that an experienced C++ coder can tell what is going on here. I could omit constness or reference, but I want to make it tight and learn in the process as well. Thanks! // In header file MyObj GetChosenThingy() const; // In Implementation file. MyObj MyDlg::GetChosenThingy() const { return m_MyObj; }

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  • Should constant contructor aguments be passed by reference or value?

    - by Mike
    When const values are passed to an object construct should they be passed by reference or value? If you pass by value and the arguments are immediately fed to initializes are two copies being made? Is this something that the compiler will automatically take care of. I have noticed that all textbook examples of constructors and intitializers pass by value but this seems inefficient to me. class Point { public: int x; int y; Point(const int _x, const int _y) : x(_x), y(_y) {} }; int main() { const int a = 1, b = 2; Point p(a,b); Point q(3,5); cout << p.x << "," << p.y << endl; cout << q.x << "," << q.y << endl; } vs. class Point { public: int x; int y; Point(const int& _x, const int& _y) : x(_x), y(_y) {} }; Both compile and do the same thing but which is correct?

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  • Left Join only returning one row

    - by Adam
    I am trying to join two tables. I would like all the columns from the product_category table (there are a total of 6 now) and count the number of products, CatCount, that are in each category from the products_has_product_category table. My query result is 1 row with the first category and a total count of 68, when I am looking for 6 rows with each individual category's count. <?php $result = mysql_query(" SELECT a.*, COUNT(b.category_id) AS CatCount FROM `product_category` a LEFT JOIN `products_has_product_category` b ON a.product_category_id = b.category_id "); while($row = mysql_fetch_array($result)) { echo ' <li class="ui-shadow" data-count-theme="d"> <a href="' . $row['product_category_ref_page'] . '.php" data-icon="arrow-r" data-iconpos="right">' . $row['product_category_name'] . '</a><span class="ui-li-count">' . $row['CatCount'] . '</span></li>'; } ?> I have been working on this for a couple of hours and would really appreciate any help on what I am doing wrong.

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  • ...Welche DB-Hintergrundprozesse sind für was zuständig?... wie ging das nochmal? Und wie heisst noch diese eine wichtige Data Dictionary View? ...

    - by britta.wolf
    ...Gab es da nicht mal ein gutes Oracle-Poster, wo man schnell nachschauen konnte und einen guten Überblick bekam? Viele Datenbankadministratoren haben das besagte Poster, das die Architektur und Prozesse sowie die Data Dictionary-Struktur der Oracle Datenbank beschreibt, vermisst! Daher wurde nun eine handliche kleine Flash-Applikation mit erweitertem Inhalt entwickelt - Oracle Database 11g: Interactive Quick Reference - die man sich hier downloaden kann (einfach auf den Button "Download now" klicken (Größe der Zip-Datei: 4.6 MB). Ist genial, muss man haben!!! :-)

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  • SQL Server 2012 - Upgrade Whitepaper

    - by JustinL
    Just a short note to mention Microsoft have released the Technical Reference Guide for upgrading to SQL Server 2012. The paper is available for download here: http://tinyurl.com/84xm5b4 There's some interesting details on approaches to upgrade, including features such as high availability, full-text search, service broker and other components (SSIS, SSAS, SSRS). Additionally, there's a (fairly) recent initiative to organise and present TechNet content more easily, there's some useful content (with interesting presentation) at the link below: http://technet.microsoft.com/en-us/library/hh393545.aspx Good luck planning your upgrades, Regards, Justin

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  • Brief material on C++ object-lifetime management and on passing and returning values/references

    - by dsign
    I was wondering if anybody can point to a post, pdf, or excerpt of a book containing the rules for C++ variable life-times and best practices for passing and returning function parameters. Things like when to pass by value and by reference, how to share ownership, avoid unnecessary copies, etc. This is not for a particular problem of mine, I've been programming in C++ for long enough to know the rules by instinct, but it is something that a lot of newcomers to the language stumble with, and I would be glad to point them to such a thing.

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  • Playing online video on iphone web, the iphone seems to cache the reference movie

    - by Mad Oxyn
    We are working on an online mobile video app, and are trying to play a reference movie on an iphone from the iphone browser. The problem is, the movie plays the first time, but when we try to play a different movie the second time, it doesnt. Quicktime gives a general error message sayin "Cannot Play Movie". More precisely this is what we are trying to do: Connect with an iPhone to a webserver that serves a reference movie (generated with quicktime pro). The ref movie automatically gets downloaded to the iphone by quicktime. Quicktime then chooses one of the 3 references in the reference movie, based on the connection speed, and tries to download the designated movie via a relative path. A servlet gets called and forwards the relative path to the right movie. This all works the first time. However the second time when we want download different movies, we get the quicktime error. Test case: Open reference movie 1 Movie plays in Quicktime Open reference movie 2 ERROR: Quicktime gives an error - Cannot Play Movie Shut down Iphone Turn Iphone on again Open reference movie 2 Iphone plays movie Open movie ERROR: Quicktime gives an error - Cannot Play Movie Did anyone encounter similar issues with quicktime and the use of reference movies and is there something we can do to work around that?

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  • Checking for empty arrays: count vs empty

    - by Dan McG
    This question on 'How to tell if a PHP array is empty' had me thinking of this question Is there a reason that count should be used instead of empty when determining if an array is empty or not? My personal thought would be if the 2 are equivalent for the case of empty arrays you should use empty because it gives a boolean answer to a boolean question. From the question linked above, it seems that count($var) == 0 is the popular method. To me, while technically correct, makes no sense. E.g. Q: $var, are you empty? A: 7. Hmmm... Is there a reason I should use count == 0 instead or just a matter of personal taste? As pointed out by others in comments for a now deleted answer, count will have performance impacts for large arrays because it will have to count all elements, whereas empty can stop as soon as it knows it isn't empty. So, if they give the same results in this case, but count is potentially inefficient, why would we ever use count($var) == 0?

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