Search Results

Search found 3255 results on 131 pages for 'pointers'.

Page 117/131 | < Previous Page | 113 114 115 116 117 118 119 120 121 122 123 124  | Next Page >

• C# array of objects - conditional validation

  - by fishdump

  Sorry about the vague title! I have an class with a number of member variables (system, zone, site, ...) public sealed class Cello { public String Company; public String Zone; public String System; public String Site; public String Facility; public String Process; //... } I have an array of objects of this class. private Cello[] m_cellos = null; // ... I need to know whether the array contains objects with the same site but different systems, zones or companies since such a situation would be illegal. I have various other checks to make but they are all along similar lines. The Array class has a number of functions that look promising but I am not very up on defining 'key selector' functions and things like that. Any suggestions or pointers would be greatly appreciated. --- Alistair.

  Read the article

• How do I close a file after catching an IOException in java?

  - by DimDom

  All, I am trying to ensure that a file I have open with BufferedReader is closed when I catch an IOException, but it appears as if my BufferedReader object is out of scope in the catch block. public static ArrayList readFiletoArrayList(String fileName, ArrayList fileArrayList) { fileArrayList.removeAll(fileArrayList); try { //open the file for reading BufferedReader fileIn = new BufferedReader(new FileReader(fileName)); // add line by line to array list, until end of file is reached // when buffered reader returns null (todo). while(true){ fileArrayList.add(fileIn.readLine()); } }catch(IOException e){ fileArrayList.removeAll(fileArrayList); fileIn.close(); return fileArrayList; //returned empty. Dealt with in calling code. } } Netbeans complains that it "cannot find symbol fileIn" in the catch block, but I want to ensure that in the case of an IOException that the Reader gets closed. How can I do that without the ugliness of a second try/catch construct around the first? Any tips or pointers as to best practise in this situation is appreciated,

  Read the article

• Does Function pointer make the program slow?

  - by drigoSkalWalker

  Hi guys. I read about function pointers in C And everyone said that will make my program run slow. Is it true? I made a program to check it. And I got the same results on both cases. (mesure the time.) So, is it bad to use fuction pointer? Thanks in advance. To response for some guys. I said 'run slow' for the time that I have compared on a loop. like this. int end = 1000; int i = 0; while (i < end) { fp = func; fp (); } When you execute this, i got the same time if I execute this. while (i < end) { func (); } So I think that function pointer have no difference of time and it don't make a program run slow as many people said.

  Read the article

• How to store and locate multiple interface types within a Delphi TInterfaceList

  - by Brian Frost

  Hi, I'm storing small interfaces from a range of objects into a single TInterfaceList 'store' with the intention of offering list of specific interface types to the end user, so each interface will expose a 'GetName' function but all other methods are unique to that interface type. For example here are two interfaces: IBase = interface //---------------------------------------- function GetName : string; //---------------------------------------- end; IMeasureTemperature = interface(IBase) //------------------------------------ function MeasureTemperature : double; //---------------------------------------- end; IMeasureHumidity = interface(IBase) //---------------------------------------- function MeasureHumidity: double; //---------------------------------------- end; I put several of these interfaces into a single TInterfaceList and then I'd like to scan the list for a specific interface type (e.g. 'IMeasureTemperature') building another list of pointers to the objects exporting those interfaces. I wish to make no assumptions about the locations of those objects, some may export more than one type of interface. I know I could do this with a class hierarchy using something like: If FList[I] is TMeasureTemperature then .. but I'd like to do something simliar with an interface type, Is this possible?

  Read the article

• What is an interface in C (COM) is it the same as a interface in C#

  - by numerical25

  Ok, I know what a interface is, but since I got into C and working with COM objects, it seems an interface in COM is a little different from the interface I know of. So what I am trying to do is bridge the gaps here cause since I been learning C, alot of things have been sounding very familiar to me but are not exactly what they seem. The interface I know of are like contracts. They are objects that have only method declarations, with no body. All classes that implement an interface must include the methods of the interface. The interface I hear about in COM seems to be just pointers. They can not retrieve objects directly but only can retrieve objects through the means of a method. Is this what a COM Interface is ?? If so, then why did they give them the same names if they are completely different. Also I just wanted to add that headers in C++ kind of remind me of the C# Interfaces. Not sure if their are any relations. But anyways, I am just trying to clear that up.

  Read the article

• Concrete examples of state sharing between multiple viewmodels (WPF MVVM)

  - by JohnMetta

  I have a WPF/Entity Framework (4.0) project with many objects. I'd like to build the application so that that I can have object selection state shared across viewmodels. For Example: We have Cars, Drivers, Passengers, and Cargo classes. We also have UserControls for CarList, DriverList, etc. and editor windows for CarEditor, DriverEditor, etc. Furthermore, we have viewmodels for all of these (CarListViewModel, DriverListViewModel, CargoEditorViewModel, etc). This all composes a dockable interface where the user can have multiple object lists, editors, and viewers open. What I want is a concrete code example of how to wireup multiple viewmodels so that selecting a car in the CarList will cause that car to go live in the CarEditorView, but also be selected in any other view for which the context is valid (such as a DriverByCarView- or just DriverList if there is a filter predicate). There are a number of suggestions and discussions based on this question. The two methods that seem to dominate are: 3018307: Discusses state sharing by mentioning a messaging subsystem 1159035: Discusses state sharing by using an enclosing viewmodel Is one of these approaches better than the other? Does anyone have a concrete example of either/both of these methods in the form of a write-up or small code project? I'm still learning WPF, so pointers to entry points for reading API fundamentals are appreciated, but looking at code examples is where I usually go. Thanks In case anyone is interested, here are some other similar discussions: 3816961: Discusses returning multiple viewmodels depending on object type (i.e. a collection of arbitrary types adhering to a specific interface) 1928130: Discusses whether it is a good idea to aggregate viewmodels as properties of other viewmodels (e.g. a MainWindow viewmodel composed of panel viewmodels) 1120061: Essentially discusses whether to have use a viewmodel-per-model strategy or a viewmodel-per-view-element strategy. 4244222: Discusses whether or not to nest the viewmodels when using a nested object hierarchy. 4429708: Discusses sharing collections between viewmodels directly, but doesn't go into detail. List item: Discusses managing multiple selections within a single viewmodel.

  Read the article

• How to convert a rectangle to TRBL CSS rect value?

  - by VLostBoy

  I'm not quite sure how to put this, but here goes... The css clip attribute is defined like so: rect(top, right, bottom, left). However, I'm exploring the use of a custom Rectangle 'class' to encapsulate some operations. The rectangle class has the attributes height, width and x, y. The x and y values are encapsulated in a Point object, and the height and width are encapsulated in a Dimension object, the rectangle being a composite of a point (its top-left location) and a dimension (width and height). So far so good. I though it would be pretty simple on the basis of having the rectangles x, y, width and height values to define the css rect attribute in terms of top, right, bottom, left, but I've become hopelessly confused- I've been googling for a while, and I can't seem to find any documentation as to what the TRBL values actually are or what they represent. For example, should I be thinking in terms of co-ordinates, in which case, surely I can describe the rectangle as a css rect using the rectangles x position for Top, x position + width for Right, the rectangles height + y for Bottom and its y position for Left... but thats a load of BS, surely? Also, surely rect is actually an inset, or have I just inverted my understanding of clip? I'd appreciate some advice. What I want to be able to do is (i) Define a rectangle using x, y, width and height (ii)Express the rectangle in TRBL form so that I can manipulate a divs clipping behaviour (iii)Change x, y, width or height and recalculate in terms of TRBL and goto (ii) I appreciate there are some other factors here, and some intermediary transforms to be done, but I've confused myself pretty badly- Can anyone give me some pointers?

  Read the article

• Implimenting Zend MVC for my existing site-first step?

  - by Joel

  Hi guys, OK-newbie question here. I'll try not to bombard SO with lots of questions-and hopefully this first one will show me the method I'll need to follow for subsequent conversions. I have a web-based calendar system that I developed, but it was coded for me procedurally (using PHP). I'm now working on learning OO and wanting to integrate this site into my localhost Zend Framework and slowly start converting parts to OO and the Zend Framework MVC process in particular. As I've said before, I understand that this will be a slow process, and when I'm done, I still probably won't have anything as OO friendly as if I had rewritten it from scratch, but I'd like to use this as a learning experience. So, I have dropped the whole site into my localhose/zend/Public folder, and everything is showing up great and linking to the database, etc. My question is-what would be the easiest first component to switch over to the MVC model? This site has a bit of everything-forms, login, authentication, some jQuery, etc. Can anyone point to a tutorial that would address what I'm trying to do? If indeed, a form would be one of the simpler things to switch, can someone walk me through those changes? Another idea is changing over all the header info, etc? Thanks for any pointers on where to start! EDIT: Also, I understand that SO is mainly for specific coding questions-I'm happy to share specific code, once I have an idea about which section to tackle first...

  Read the article

• autorelease object not confirming protocol does not give any warning

  - by Sahil Wasan

  I have a class "ABC" and its method which returns non autoreleases object of that class. @interface ABC:NSObject +(ABC *)aClassMethodReturnsObjectWhichNotAutoreleased; @end @implementation ABC +(ABC *)aClassMethodReturnsObjectWhichNotAutoreleased{ ABC *a = [[ABC alloc]init]; return a; } @end If I have a protocol Foo. @Protocol Foo @required -(void)abc; @end My ABC class is "not" confirming Foo protocols. 1st call id<Foo> obj = [ABC aClassMethodReturnsObjectWhichNotAutoreleased]; //show warning It shows warning "Non Compatible pointers.." thats good.Abc did not confirm protocol Foo BUT 2nd call id<Foo> obj = [NSArray arrayWithObjects:@"abc",@"def",nil]; // It will "not" show warning as it will return autorelease object.NSArray don't confirm protocol Foo In first call compiler gives warning and in second call compiler is not giving any warning.I think that is because i am not returning autorelease object. Why is compiler not giving warning in 2nd call as NSArray is also not confirming FOO Thanks in advance

  Read the article

• Convenient way to do "wrong way rebase" in git?

  - by Kaz

  I want to pull in newer commits from master into topic, but not in such a way that topic changes are replayed over top of master, but rather vice versa. I want the new changes from master to be played on top of topic, and the result to be installed as the new topic head. I can get exactly the right object if I rebase master to topic, the only problem being that the object is installed as the new head of master rather than topic. Is there some nice way to do this without manually shuffling around temporary head pointers? Edit: Here is how it can be achieved using a temporary branch head, but it's clumsy: git checkout master git checkout -b temp # temp points to master git rebase topic # topic is brought into temp, temp changes played on top Now we have the object we want, and it's pointed at by temp. git checkout topic git reset --hard temp Now topic has it; and all that is left is to tidy up by deleting temp: git branch -d temp Another way is to to do away with temp and just rebase master, and then reset topic to master. Finally, reset master back to what it was by pulling its old head from the reflog, or a cut-and-paste buffer.

  Read the article

• MySQL running on an EC2 m1.small instance has high load but low memory usage, possible resolutions?

  - by Tosh

  I have a MySQL server 5.0.75 Ubuntu, on an m1.small instance running on Amazon's EC2 as part of an application. During peak usage the server load will rise very high, while the memory usage stays low and the application server is no longer responsive since it's waiting for query results. The application server has only 5-8 apache processes running (mod_perl processes). The data directory uses only 140MB of data so the MyIsam tables aren't very big. The queries are pretty complicated with some big joins being performed, and the application makes a lot of queries. mysqltuner reports everything OK except "Maximum possible memory usage: 1.7G (99% of installed RAM)" but I'm nowhere close to using that. My question is, where should I be looking to fix this? Is this something that can be tuned away, or do I just need a larger instance/server? Googling indicates either or also upgrading MySQL server. Any pointers in the right direction would be greatly appreciated, thanks! EDIT: I just discovered this in my slow queries log: # Time: 101116 11:17:00 # User@Host: user[pass] @ [host] # Query_time: 4063 Lock_time: 1035 Rows_sent: 0 Rows_examined: 19960174 SELECT * FROM contacts WHERE contacts.contact_id IN (SELECT external_id FROM contact_relations WHERE external_table = 'contacts' AND contact_id IN (SELECT contact_id FROM contacts WHERE (company_name like '%%butan%%%' OR country like '%%butan%%%' OR city like '%%butan%%%' OR email1 like '%%butan%%%') AND (company_name is not null and company_name != ''))); Which actually brings up a different but related question: If I have a contact table containing: John Smith,The Fun Factory,555-1212,[email protected] What's the best way to search for that record using "factory" as a search key? Fulltext rarely seems to find items in the middle of a word, for example "actor" should bring up "Factory"

  Read the article

• Embedded scripting engine in .Net app

  - by Nate

  I am looking to replace an old control being used for scripting an application. The control used to be called SAX Basic, but is now called WinWrap. It provides us with two primary functions. 1) It's a scripting engine (VB) 2) It has a GUI for developing and debugging scripts that get run in the hosting application. The first feature it provides is actually pretty easy to replace. There are so many great methods of running just about any kind of code at runtime that it's almost a non-issue. Just about any language targeting the .Net runtime will work for us. We've looked at running C#, PowerShell, VB.Net, IronPython, etc. I've also taken a brief look at Lua and F#, but honestly the language isn't the biggest barrier here. Now, for the hard part that seems to keep getting me stuck. We want a code editor, and debugger. Something simple, not unlike PowerShell's ISE would be fine. Just as long as a file could be created, saved, debugged and executed. I'm currently looking into Visual Studio 2010 Shell (Isolated) and I'm also looking at the feasibility of embedding PowerShell ISE in my application. Are there any other editor's I could embed/use in my application? Purchasing a product is not out of the question. It comes down to a combination of ease of use, how well it meets our needs, and how simple deployment and licensing is for developers. Thanks for the pointers

  Read the article

• Image Resizing and Compression

  - by GSTAR

  Hi guys, I'm implementing an image upload facility for my website. The uploading facility is complete but what I'm working on at the moment is manipulating the images. For this task I am using PHPThumb (http://phpthumb.gxdlabs.com). Anyway as I go along I'm coming across potential issues, to do with resizing and compression. Basically I want to acheive the following results: The ideal image dimensions are: 800px width, 600px height. If an uploaded image exceeds either of these dimensions, it will need be resized to meet the requirements. Otherwise, leave as it is. The ideal file size is 200kb. If an uploaded image exceeds this then it will need to be compressed to meet this requirement. Otherwise, leave as it is. So in a nutshell: 1) Check the dimensions, resize if required. 2) Check the filesize, compress if required. Has anybody done anything like this / could you give me some pointers? Is PHPThumb the correct tool to do this in?

  Read the article

• PDF search on the iPhone

  - by pt2ph8

  After two days trying to read annotations from a PDF using Quartz, I've managed to do it and posted my code. Now I'd like to do the same for another frequently asked question: searching PDF documents with Quartz. Same situation as before, this question has been asked many times with almost no practical answers. So I need some pointers first, as I still haven't implemented this myself. What I tried: I tried using CGPDFScannerScan handling the TJ and Tj operators - returns the right text on some PDF, whereas on other documents it returns mostly random letters. Maybe it's related to text encoding? Someone pointed out that text blocks (marked by BT/ET operators) should be handled instead, but I still haven't managed to do so. Anyone managed to extract text from any PDF? After that, searching should be easy by storing all the text in a NSMutableString and using rangeOfString (if there's a better way please let me know). But then how to highlight the result? I know there are a few operators to find the glyph sizes, so I could calculate the resulting rect based on those values, but I've been reading the spec for hours... it's a bloated mess and I'm going insane. Anyone with a practical explanation? Thanks.

  Read the article

• Printing in Silverlight 4

  - by Number8

  Hello, We have an application structured roughly like this: <Grid x:Name="LayoutRoot"> <ScrollViewer> <Canvas x:Name="canvas"> <StackPanel> < Button /><Slider /><Button /></StackPanel> <custom:Blob /> <custom:Blob /> <custom:Blob /> </Canvas> </ScrollViewer> </Grid> Each Blob consists of 1 or more rectangles, lines, and text boxes; they are positioned anywhere on the canvas. If I print the document using the LayoutRoot: PrintDocument pd = new PrintDocument(); pd += (s, pe) => { pe.PageVisual = LayoutRoot; }; pd.Print("Blobs"); ... it is like a print-screen -- the scrollbars, the sliders, the blobs that are visible -- are printed. If I set PageVisual = canvas, nothing is printed. How can I get all the blob objects, and just those objects, to print? Do I need to copy them into another container, and give that container to PageVisual? Can I use a ViewBox to make sure they all fit on one page? Thanks for any pointers....

  Read the article

• VS2008 Link Error Using SafeInt3.hpp in 64bit mode.

  - by photo_tom

  I have the below code that links and runs fine in 32bit mode - #include "safeint3.hpp" typedef SafeInt<SIZE_T> SAFE_SIZE_T; SAFE_SIZE_T sizeOfCache; SAFE_SIZE_T _allocateAmt; Where safeint3.hpp is current version that can be found on Codeplex SafeInt. For those who are unaware of it, safeint is a template class that makes working with different integer types and sizes "safe". To quote channel 9 video on software - "it writes the code that you should". Which is my case. I have a class that is managing a large in-memory cache of objects (6gb) and I am very concerned about making sure that I don't have overflow/underflow issues on my pointers/sizes/other integer variables. In this use, it solves many problems. My problem is coming when moving from 32bit dev mode to 64bit production mode. When I build the app in this mode, I'm getting the following linker warnings - 1>cachecontrol.obj : warning LNK4006: "bool __cdecl IntrinsicMultiplyUint64(unsigned __int64 const &,unsigned __int64 const &,unsigned __int64 *)" (?IntrinsicMultiplyUint64@@YA_NAEB_K0PEA_K@Z) already defined in ImageInRamCache.obj; second definition ignored 1>cachecontrol.obj : warning LNK4006: "bool __cdecl IntrinsicMultiplyInt64(__int64 const &,__int64 const &,__int64 *)" (?IntrinsicMultiplyInt64@@YA_NAEB_J0PEA_J@Z) already defined in ImageInRamCache.obj; second definition ignored While I understand I can ignore the error, I would like either (a) prevent the warning from occurring or (b) make it disappear so that my QA department doesn't flag it as a problem. And after spending some time researching it, I cannot find a way to do either.

  Read the article

• PHP Access property of a class from within a class instantiated in the original class.

  - by Iain

  I'm not certain how to explain this with the correct terms so maybe an example is the best method... $master = new MasterClass(); $master->doStuff(); class MasterClass { var $a; var $b; var $c; var $eventProccer; function MasterClass() { $this->a = 1; $this->eventProccer = new EventProcess(); } function printCurrent() { echo '<br>'.$this->a.'<br>'; } function doStuff() { $this->printCurrent(); $this->eventProccer->DoSomething(); $this->printCurrent(); } } class EventProcess { function EventProcess() {} function DoSomething() { // trying to access and change the parent class' a,b,c properties } } My problem is i'm not certain how to access the properties of the MasterClass from within the EventProcess-DoSomething() method? I would need to access, perform operations on and update the properties. The a,b,c properties will be quite large arrays and the DoSomething() method would be called many times during the execuction of the script. Any help or pointers would be much appreciated :)

  Read the article

• C++ and Dependency Injection in unit testing

  - by lhumongous

  Suppose I have a C++ class like so: class A { public: A() { } void SetNewB( const B& _b ) { m_B = _b; } private: B m_B; } In order to unit test something like this, I would have to break A's dependency on B. Since class A holds onto an actual object and not a pointer, I would have to refactor this code to take a pointer. Additionally, I would need to create a parent interface class for B so I can pass in my own fake of B when I test SetNewB. In this case, doesn't unit testing with dependency injection further complicate the existing code? If I make B a pointer, I'm now introducing heap allocation, and some piece of code is now responsible for cleaning it up (unless I use ref counted pointers). Additionally, if B is a rather trivial class with only a couple of member variables and functions, why introduce a whole new interface for it instead of just testing with an instance of B? I suppose you could make the argument that it would be easier to refactor A by using an interface. But are there some cases where two classes might need to be tightly coupled?

  Read the article

• Retain numerical precision in an R data frame?

  - by David

  When I create a dataframe from numeric vectors, R seems to truncate the value below the precision that I require in my analysis: data.frame(x=0.99999996) returns 1 (see update 1) I am stuck when fitting spline(x,y) and two of the x values are set to 1 due to rounding while y changes. I could hack around this but I would prefer to use a standard solution if available. example Here is an example data set d <- data.frame(x = c(0.668732936336141, 0.95351462456867, 0.994620622127435, 0.999602102672081, 0.999987126195509, 0.999999955814133, 0.999999999999966), y = c(38.3026509783688, 11.5895099585560, 10.0443344234229, 9.86152339768516, 9.84461434575695, 9.81648333804257, 9.83306725758297)) The following solution works, but I would prefer something that is less subjective: plot(d$x, d$y, ylim=c(0,50)) lines(spline(d$x, d$y),col='grey') #bad fit lines(spline(d[-c(4:6),]$x, d[-c(4:6),]$y),col='red') #reasonable fit Update 1 Since posting this question, I realize that this will return 1 even though the data frame still contains the original value, e.g. > dput(data.frame(x=0.99999999996)) returns structure(list(x = 0.99999999996), .Names = "x", row.names = c(NA, -1L), class = "data.frame") Update 2 After using dput to post this example data set, and some pointers from Dirk, I can see that the problem is not in the truncation of the x values but the limits of the numerical errors in the model that I have used to calculate y. This justifies dropping a few of the equivalent data points (as in the example red line).

  Read the article

• Importing a C DLL's functions into a C++ program

  - by bobobobo

  I have a 3rd party library that's written in C. It exports all of its functions to a DLL. I have the .h file, and I'm trying to load the DLL from my C++ program. The first thing I tried was surrounding the parts where I #include the 3rd party lib in #ifdef __cplusplus extern "C" { #endif and, at the end #ifdef __cplusplus } // extern "C" #endif But the problem there was, all of the DLL file function linkage looked like this in their header files: a_function = (void *)GetProcAddress(dll, "a_function"); While really a_function had type int (*a_function) (int *). Apparently MSVC++ compiler doesn't like this, while MSVC compiler does not seem to mind. So I went through (brutal torture) and fixed them all to the pattern typedef int (*_a_function) (int *); _a_function a_function ; Then, to link it to the DLL code, in main(): a_function = (_a_function)GetProcAddress(dll, "a_function"); This SEEMS to make the compiler MUCH, MUCH happier, but it STILL complains with this final set of 143 errors, each saying for each of the DLL link attempts: error LNK2005: _a_function already defined in main.obj main.obj Multiple symbol definition errors.. sounds like a job for extern! SO I went and made ALL the function pointer declarations as follows: function_pointers.h typedef int (*_a_function) (int *); extern _a_function a_function ; And in a cpp file: function_pointers.cpp #include "function_pointers.h" _a_function a_function ; ALL fine and dandy.. except for linker errors now of the form: error LNK2001: unresolved external symbol _a_function main.obj Main.cpp includes "function_pointers.h", so it should know where to find each of the functions.. I am bamboozled. Does any one have any pointers to get me functional? (Pardon the pun..)

  Read the article

• Change URL Submitted to Depending on Form Selection

  - by Chris

  I have a form which I need to submit to one of three different URLs depending on a selection made in the form. I suspect the easiest solution is to use jQuery to insert the appropriate path before the rest of the form parameters as the selection is made, but not sure on what the code would be. Any pointers greratly appreciated! <form id="myForm" action='/booking/default-path' accept-charset='utf-8' method='get'> <select name="paramA" id="paramA"> <option id="optionA" value="A" selected="selected">Option A</option> <option id="optionB" value="B">Option B</option> </select> <select name="currency" id="currency"> <option id="GBP" value="GBP" selected="selected">British Pounds</option> <option id="EUR" value="EUR">Euros</option> <option id="USD" value="USD">US Dollars</option> </select> <input type="submit" value="submit" id="submit" name="submit" /> </form> Where the three different URLs would be: ../booking/default-path-gbp?...[params here]... ../booking/default-path-eur?...[params here]... ../booking/default-path-usd?...[params here]... I know it would be a lot easier to incorporate the parameter in the usual way and just use one submission URL root, but unfortunately I'm submitting to an eComms system out of my control and am stuck with having to find a solution to this. Should be easy I think, but not sure where to start, jQuery used elsewhere, so would prefer to use this framework in any solutions.

  Read the article

• std::map keys in C++

  - by Soumava

  I have a requirement to create two different maps in C++. The Key is of type CHAR * and the Value is a pointer to a struct. I am filling 2 maps with these pairs, in separate iterations. After creating both maps I need find all such instances in which the value of the string referenced by the CHAR * are same. For this i am using the following code : typedef struct _STRUCTTYPE { .. } STRUCTTYPE, *PSTRUCTTYPE; typedef pair {CHAR *,PSTRUCTTYPE} kvpair; .. CHAR *xyz; PSTRUCTTYPE abc; after filling the information; Map.insert (kvpair(xyz,abc)); the above is repeated x times for the first map, and y times for the second map. after both are filled out; std::map {CHAR *, PSTRUCTTYPE} :: iterator Iter,findIter; for (Iter=iteratedMap-begin();Iter!=iteratedMap-end();mapIterator++) { char *key = Iter-first; printf("%s\n",key); findIter=otherMap-find(key); //printf("%u",findIter-second); if (findIter!=otherMap-end()) { printf("Match!\n"); } } The above code does not show any match, although the list of keys in both maps show obvious matches. My understanding is that the equals operator for CHAR * just equates the memory address of the pointers. My question is, what should i do to alter the equals operator for this type of key or could I use a different datatype for the string? *note : {} has been used instead of angle brackets as the content inside angle brackets was not showing up in the post.

  Read the article

• Best way to build an application based on R?

  - by Prasad Chalasani

  I'm looking for suggestions on how to go about building an application that uses R for analytics, table generation, and plotting. What I have in mind is an application that: displays various data tables in different tabs, somewhat like in Excel, and the columns should be sortable by clicking. takes user input parameters in some dialog windows. displays plots dynamically (i.e. user-input-dependent) either in a tab or in a new pop-up window/frame Note that I am not talking about a general-purpose fron-end/GUI for exploring data with R (like say Rattle), but a specific application. Some questions I'd like to see addressed are: Is an entirely R-based approach even possible ( on Windows ) ? The following passage from the Rattle article in R-Journal intrigues me: It is interesting to note that the first implementation of Rattle actually used Python for implementing the callbacks and R for the statistics, using rpy. The release of RGtk2 allowed the interface el- ements of Rattle to be written directly in R so that Rattle is a fully R-based application If it's better to use another language for the GUI part, which language is best suited for this? I'm looking for a language where it's relatively "painless" to build the GUI, and that also integrates very well with R. From this StackOverflow question How should I do rapid GUI development for R and Octave methods (possibly with Python)? I see that Python + PyQt4 + QtDesigner + RPy2 seems to be the best combo. Is that the consensus ? Anyone have pointers to specific (open source) applications of the type I describe, as examples that I can learn from?

  Read the article

• Best (Java) book for understanding 'under the bonnet' for programming?

  - by Ben

  What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

  Read the article

• How to access variables in shared memory

  - by user1723361

  I am trying to create a shared memory segment containing three integers and an array. The segment is created and a pointer is attached, but when I try to access the values of the variables (whether changing, printing, etc.) I get a segmentation fault. Here is the code I tried: #include <stdio.h> #include <stdbool.h> #include <stdlib.h> #include <errno.h> #include <sys/types.h> #include <sys/ipc.h> #include <sys/sem.h> #define SIZE 10 int* shm_front; int* shm_end; int* shm_count; int* shm_array; int shm_size = 3*sizeof(int) + sizeof(shm_array[SIZE]); int main(int argc, char* argsv[]) { int shmid; //create shared memory segment if((shmid = shmget(IPC_PRIVATE, shm_size, 0644)) == -1) { printf("error in shmget"); exit(1); } //obtain the pointer to the segment if((shm_front = (int*)shmat(shmid, (void *)0, 0)) == (void *)-1) { printf("error in shmat"); exit(1); } //move down the segment to set the other pointers shm_end = shm_front + 1; shm_count = shm_front + 2; shm_array = shm_front + 3; //tests on shm //*shm_end = 10; //gives segmentation fault //printf("\n%d", *shm_front); //gives segmentation fault //clean-up //get rid of shared memory shmdt(shm_front); shmctl(shmid, IPC_RMID, NULL); //printf("\n\n"); return 0; } I tried accessing the shared memory by dereferencing the pointer to the struct, but got a segmentation fault each time.

  Read the article

< Previous Page | 113 114 115 116 117 118 119 120 121 122 123 124  | Next Page >