Search Results

Search found 11020 results on 441 pages for 'pass summit'.

Page 47/441 | < Previous Page | 43 44 45 46 47 48 49 50 51 52 53 54  | Next Page >

  • In the following implementation of static_strlen, why are the & and parentheses around str necessary

    - by Ben
    If I change the type to const char str[Len], I get the following error: error: no matching function for call to ‘static_strlen(const char [5])’ Am I correct that static_strlen expects an array of const char references? My understanding is that arrays are passed as pointers anyway, so what need is there for the elements to be references? Or is that interpretation completely off-the-mark? #include <iostream> template <size_t Len> size_t static_strlen(const char (&str)[Len]) { return Len - 1; } int main() { std::cout << static_strlen("oyez") << std::endl; return 0; }

    Read the article

  • Passing objects by reference or not in C#

    - by Piku
    Suppose I have a class like this: public class ThingManager { List<SomeClass> ItemList; public void AddToList (SomeClass Item) { ItemList.Add(Item); } public void ProcessListItems() { // go through list one item at a time, get item from list, // modify item according to class' purpose } } Assume "SomeClass" is a fairly large class containing methods and members that are quite complex (List<s and arrays, for example) and that there may be a large quantity of them, so not copying vast amounts of data around the program is important. Should the "AddToList" method have "ref" in it or not? And why? It's like trying to learn pointers in C all over again ;-) (which is probably why I am getting confused, I'm trying to relate these to pointers. In C it'd be "SomeClass *Item" and a list of "SomeClass *" variables)

    Read the article

  • C++ Passing `this` into method by reference

    - by David
    I have a class constructor that expects a reference to another class object to be passed in as an argument. I understand that references are preferable to pointers when no pointer arithmetic will be performed or when a null value will not exist. This is the header declaration of the constructor: class MixerLine { private: MIXERLINE _mixerLine; public: MixerLine(const MixerDevice& const parentMixer, DWORD destinationIndex); ~MixerLine(); } This is the code that calls the constructor (MixerDevice.cpp): void MixerDevice::enumerateLines() { DWORD numLines = getDestinationCount(); for(DWORD i=0;i<numLines;i++) { MixerLine mixerLine( this, i ); // other code here removed } } Compilation of MixerDevice.cpp fails with this error: Error 3 error C2664: 'MixerLine::MixerLine(const MixerDevice &,DWORD)' : cannot convert parameter 1 from 'MixerDevice *const ' to 'const MixerDevice &' But I thought pointer values could be assigned to pointers, e.g. Foo* foo = new Foo(); Foo& bar = foo;

    Read the article

  • Passing optional parameter by reference in c++

    - by Moomin
    I'm having a problem with optional function parameter in C++ What I'm trying to do is to write function with optional parameter which is passed by reference, so that I can use it in two ways (1) and (2), but on (2) I don't really care what is the value of mFoobar. I've tried such a code: void foo(double &bar, double &foobar = NULL) { bar = 100; foobar = 150; } int main() { double mBar(0),mFoobar(0); foo(mBar,mFoobar); // (1) cout << mBar << mFoobar; mBar = 0; mFoobar = 0; foo(mBar); // (2) cout << mBar << mFoobar; return 0; } but it crashes at void foo(double &bar, double &foobar = NULL) with message : error: default argument for 'double& foobar' has type 'int' Is it possible to solve it without function overloading? Thanks in advance for any suggestions. Pawel

    Read the article

  • Most efficient way of checking for a return from a function call in Perl

    - by Gaurav Dadhania
    I want to add the return value from the function call to an array iff something is returned (not by default, i.e. if I have a return statement in the subroutine.) so I'm using unshift @{$errors}, "HashValidator::$vfunction($hashref)"; but this actually adds the string of the function call to the array. I also tried unshift @{$errors}, $temp if defined my $temp = "HashValidator::$vfunction($hashref)"; with the same result. What would a perl one-liner look like that does this efficiently (I know I can do the ugly, multi-line check but I want to learn). Thanks,

    Read the article

  • C++: Reference and Pointer question (example regarding OpenGL)

    - by Jay
    I would like to load textures, and then have them be used by multiple objects. Would this work? class Sprite { GLuint* mTextures; // do I need this to also be a reference? Sprite( GLuint* textures ) // do I need this to also be a reference? { mTextures = textures; } void Draw( textureNumber ) { glBindTexture( GL_TEXTURE_2D, mTextures[ textureNumber ] ); // drawing code } }; // normally these variables would be inputed, but I did this for simplicity. const int NUMBER_OF_TEXTURES = 40; const int WHICH_TEXTURE = 10; void main() { std::vector<GLuint> the_textures; the_textures.resize( NUMBER_OF_TEXTURES ); glGenTextures( NUMBER_OF_TEXTURES, &the_textures[0] ); // texture loading code Sprite the_sprite( &the_textures[0] ); the_sprite.Draw( WHICH_TEXTURE ); } And is there a different way I should do this, even if it would work? Thanks.

    Read the article

  • Passing variables from SQL proceedure to PHP

    - by Sam Corbet
    I am trying to create an sql proceedure that will return the results back to the php page. I want to be able to call the procedure as follows from the php call procedure_name($var1) which will run this script: -- --------------------------------------------------------------------------------- -- pUIGetCliStmtGenFlag -- -- This procedure returns the status of the Trading Period: -- -- --------------------------------------------------------------------------------- drop procedure if exists pUIGetCliStmtGenFlag; delimiter // create procedure pUIGetCliStmtGenFlag( IN pTradingPeriodMonth DATE ) MODIFIES SQL DATA COMMENT 'Checks if the TP has been closed' begin SELECT trading_period_month, dt_end, amt_traded_system_ccy FROM ca_trading_period WHERE trading_period_month=$var1 -- If amt_traded_system_ccy is NULL give the TP an open status otherwise mark as closed IF amt_traded_system_ccy is NULL $tpstatus='open' ELSE $tpstatus='closed' end; // delimiter ; I then want to be able to use $tpstatus in the rest of the php script. I know this is simple but this is completely new to me and I cant find the correct method

    Read the article

  • void foo(int &x) -> Ruby? Passing integers by reference?

    - by Earlz
    Hello, as a way to spice up my C++ programming homework, I've decided to instead of typing the C++ from the book onto my computer, instead reforming it in Ruby. Yes it's a bit silly, but I'm bored. Anyway, I'm having trouble converting this kind of function to Ruby void swap(int &a,int &b){ int c=b; b=a; a=c } What would the equivalent ruby code looking inside a function ?

    Read the article

  • JNA Passing Structure By Reference Help

    - by tyeh26
    Hi all, I'm trying to use JNA to talk over a USB device plugged into the computer. Using Java and a .dll that was provided to me. I am having trouble with the Write function: C code: typedef struct { unsigned int id; unsigned int timestamp; unsigned char flags; unsigned char len; unsigned char data[16]; } CANMsg; CAN_STATUS canplus_Write( CANHANDLE handle, //long CANMsg *msg ); Java Equivalent: public class CANMsg extends Structure{ public int id = 0; public int timestamp = 0; public byte flags = 0; public byte len = 8; public byte data[] = new byte[16]; } int canplus_Write(NativeLong handle, CANMsg msg); I have confirmed that I can open and close the device. The close requires the NativeLong handle, so i am assuming that the CANMsg msg is the issue here. I have also confirmed that the device works when tested with C only code. I have read the the JNA documentation thoroughly... I think. Any pointers. Thanks all.

    Read the article

  • Powershell: splatting after passing hashtable by reference

    - by user1815871
    Powershell newbie ... I recently learned about splatting — very useful. I ran into a snag when I passed a hash table by reference to a function for splatting purposes. (For brevity's sake — a silly example.) Function AllMyChildren { param ( [ref]$ReferenceToHash } get-childitem @ReferenceToHash.Value # etc.etc. } $MyHash = @{ 'path' = '*' 'include' = '*.ps1' 'name' = $null } AllMyChildren ([ref]$MyHash) Result: an error ("Splatted variables cannot be used as part of a property or array expression. Assign the result of the expression to a temporary variable then splat the temporary variable instead."). Tried this afterward: $newVariable = $ReferenceToHash.Value get-childitem @NewVariable That did work and seemed right per the error message. But: is it the preferred syntax in a case like this? (An oh, look, it actually worked solution isn't always a best practice. My approach here strikes me as "Perl-minded" and perhaps in Powershell passing by value is better, though I don't yet know the syntax for it w.r.t. a hash table.)

    Read the article

  • g++ doesn't think I'm passing a reference

    - by Ben Jones
    When I call a method that takes a reference, g++ complains that I'm not passing a reference. I thought that the caller didn't have to do anything different for PBR. Here's the offending code: //method definition void addVertexInfo(VertexInfo &vi){vertexInstances.push_back(vi);} //method call: sharedVertices[index]->addVertexInfo(VertexInfo(n1index, n2index)); And here's the error: GLUtils/GLMesh.cpp: In member function 'void GLMesh::addPoly(GLIndexedPoly&)': GLUtils/GLMesh.cpp:110: error: no matching function for call to 'SharedVertexInfo::addVertexInfo(VertexInfo)' GLUtils/GLMesh.h:93: note: candidates are: void SharedVertexInfo::addVertexInfo(VertexInfo&)

    Read the article

  • How to access the element of a list/vector that passed by reference in C++

    - by bsoundra
    Hi all, The problem is passing lists/vectors by reference int main(){ list<int> arr; //Adding few ints here to arr func1(&arr); return 0; } void func1(list<int> * arr){ // How Can I print the values here ? //I tried all the below , but it is erroring out. cout<<arr[0]; // error cout<<*arr[0];// error cout<<(*arr)[0];//error //How do I modify the value at the index 0 ? func2(arr);// Since it is already a pointer, I am passing just the address } void func2(list<int> *arr){ //How do I print and modify the values here ? I believe it should be the same as above but // just in case. } Is the vectors any different from the lists ? Thanks in advance. Any links where these things are explained elaborately will be of great help. Thanks again.

    Read the article

  • Should the argument be passed by reference in this .net example?

    - by Hamish Grubijan
    I have used Java, C++, .Net. (in that order). When asked about by-value vs. by-ref on interviews, I have always done well on that question ... perhaps because nobody went in-depth on it. Now I know that I do not see the whole picture. I was looking at this section of code written by someone else: XmlDocument doc = new XmlDocument(); AppendX(doc); // Real name of the function is different AppendY(doc); // ditto When I saw this code, I thought: wait a minute, should not I use a ref in front of doc variable (and modify AppendX/Y accordingly? it works as written, but made me question whether I actually understand the ref keyword in C#. As I thought about this more, I recalled early Java days (college intro language). A friend of mine looked at some code I have written and he had a mental block - he kept asking me which things are passed in by reference and when by value. My ignorant response was something like: Dude, there is only one kind of arg passing in Java and I forgot which one it is :). Chill, do not over-think and just code. Java still does not have a ref does it? Yet, Java hackers seem to be productive. Anyhow, coding in C++ exposed me to this whole by reference business, and now I am confused. Should ref be used in the example above? I am guessing that when ref is applied to value types: primitives, enums, structures (is there anything else in this list?) it makes a big difference. And ... when applied to objects it does not because it is all by reference. If things were so simple, then why would not the compiler restrict the usage of ref keyword to a subset of types. When it comes to objects, does ref serve as a comment sort of? Well, I do remember that there can be problems with null and ref is also useful for initializing multiple elements within a method (since you cannot return multiple things with the same easy as you would do in Python). Thanks.

    Read the article

  • Objects in Java ArrayList don't get updated.

    - by Sbm007
    This is going to be a very long post, hopefully you can understand what I'm talking about and I appreciate any help. Thanks Basically, I've created a personal, non-commercial project (which I don't plan to release) that can read ZIP and RAR files. It can only read the contents in the archive, the folders inside, the files inside the folders and its properties (such as last modified date, last modified time, CRC checksum, uncompressed size, compressed size and file name). It can't extract files either, so it's really a ZIP/RAR viewer if you may. Anyway that's slightly irrelevant to my problem but I thought I'd give you some background info. Now for my problem: I can successfully list all the folders and files inside a ZIP archive, so now I want to take that raw input and link it together in some useful way. I made 2 classes: ArchiveFile (represents a file inside a ZIP) and ArchiveFolder (represents a folder inside a ZIP). They both have some useful methods such as getLastModifiedDate, getName, getPath and so on. But the difference is that ArchiveFolder can hold an ArrayList of ArchiveFile's and additional ArchiveFolder's (think of this as files and folders inside a folder). Now I want to populate my raw input into one root ArchiveFolder, which will have all the files in the root dir of the ZIP in the ArchiveFile's ArrayList and any additional folders in the root dir of the ZIP in the ArchiveFolder's ArrayList (and this process can continue on like this like a chain reaction (more files/folders in that ArchiveFolder etc etc). So I came up with the following code: while (archive.hasMore()) { String path = ""; ArchiveFolder current = root; String[] contents = archive.getName().split("/"); for (int x = 0; x < contents.length; ++x) { if (x == (contents.length - 1) && !archive.getName().endsWith("/")) { // If on last item and item is a file path += contents[x]; // Update final path ArchiveFile file = new ArchiveFile(path, contents[x], archive.getUncompressedSize(), archive.getCompressedSize(), archive.getModifiedTime(), archive.getModifiedDate(), archive.getCRC()); current.addFile(file); // Create and add the file to the current ArchiveFolder } else if (x == (contents.length - 1)) { // Else if we are on last item and it is a folder path += contents[x] + "/"; // Update final path ArchiveFolder folder = new ArchiveFolder(path, contents[x], archive.getModifiedTime(), archive.getModifiedDate()); current.addFolder(folder); // Create and add this folder to the current ArchiveFile } else { // Else if we are still traversing through the path path += contents[x] + "/"; // Update path ArchiveFolder folder = new ArchiveFolder(path, contents[x]); current.addFolder(folder); // Create and add folder (remember we do not know the modified date/time as all we know is the path, so we can deduce the name only) current = folder; // Update current ArchiveFolder to the newly created one for the next iteration of the for loop } } archive.getNext(); } Assume that root is the root ArchiveFolder (initially empty). And that archive.getName() returns the name of the current file OR folder in the following fashion: file.txt or folder1/file2.txt or folder4/folder2/ (this is a empty folder) etc. So basically the relative path from the root of the ZIP archive. Please read through the comments in the above code to familiarize yourself with it. Also assume that the addFolder method in an ArchiveFile, only adds the folder if it doesn't exist already (so there are no multiple folders) and it also updates the time and date of an existing folder if it is blank (ie it was a intermediate folder we only knew the name of, but now we know its details). The code for addFolder is (pretty self-explanitory): public void addFolder(ArchiveFolder folder) { int loc = folders.indexOf(folder); // folders is the ArrayList containing ArchiveFolder's if (loc == -1) { folders.add(folder); } else { ArchiveFolder real = folders.get(loc); if (real.time == null) { real.setTime(folder.getTime()); real.setDate(folder.getDate()); } } } So I can't see anything wrong with the code, it works and after finishing, the root ArchiveFolder contains all the files in the root of the ZIP as I want it to, and it contains all the direcories in the root folder as I want it to. So you'd think it works as expected, but no the ArchiveFolder's in the root folder don't contain the data inside those 'child' folders, it's just a blank folder with no additional files and folders (while it does really contain some more files/folders when viewed in WinZip). After debugging using Eclipse, the for loop does iterate through all the files (even those not included above), so this led me to believe that there is a problem with this line of the code: current = folder; What it does is, it updates the current folder (used as an intermediate by the loop) to the newly added folder. I thought Java passed by reference and thus all new operations and new additions in future ArchiveFile's and ArchiveFolder's are automatically updated, and parent ArchiveFolder's will be updated accordingly. But that does not appear to be the case? I know this is a long ass post and I really hope anyone can help me out with this. Thanks in advance.

    Read the article

  • C++ Type error with Object versus Object reference

    - by muddybruin
    I have the following function (which worked in Visual Studio): bool Plane::contains(Vector& point){ return normalVector.dotProduct(point - position) < -doubleResolution; } When I compile it using g++ version 4.1.2 , I get the following error: Plane.cpp: In member function âvirtual bool Plane::contains(Vector&)â: Plane.cpp:36: error: no matching function for call to âVector::dotProduct(Vector)â Vector.h:19: note: candidates are: double Vector::dotProduct(Vector&) So as you can see, the compiler thinks (point-position) is a Vector but it's expecting Vector&. What's the best way to fix this? I verified that this works: Vector temp = point-position; return normalVector.dotProduct(temp) < -doubleResolution; But I was hoping for something a little bit cleaner. I heard a suggestion that adding a copy constructor might help. So I added a copy constructor to Vector (see below), but it didn't help. Vector.h: Vector(const Vector& other); Vector.cpp: Vector::Vector(const Vector& other) :x(other.x), y(other.y), z(other.z), homogenous(other.homogenous) { }

    Read the article

  • Passing template into boost function

    - by Ockonal
    template <class EventType> class IEvent; class IEventable; typedef boost::function<void (IEventable&, IEvent&)> behaviorRef; What is the right way for passing template class IEvent into boost function? With this code I get: error: functional cast expression list treated as compound expression error: template argument 1 is invalid error: invalid type in declaration before ‘;’ token

    Read the article

  • Referencing variables in a structure / C++

    - by user1628622
    Below, I provided a minimal example of code I created. I managed to get this code working, but I'm not sure if the practice being employed is sound. In essence, what I am trying to do is have the 'Parameter' class reference select elements in the 'States' class, so variables in States can be changed via Parameters. Questions I have: is the approach taken OK? If not, is there a better way to achieve what I am aiming for? Example code: struct VAR_TYPE{ public: bool is_fixed; // If is_fixed = true, then variable is a parameter double value; // Numerical value std::string name; // Description of variable (to identify it by name) }; struct NODE{ public: VAR_TYPE X, Y, Z; /* VAR_TYPE is a structure of primitive types */ }; class States{ private: std::vector <NODE_ptr> node; // shared ptr to struct NODE std::vector <PROP_DICTIONARY_ptr> property; // CAN NOT be part of Parameter std::vector <ELEMENT_ptr> element; // CAN NOT be part of Parameter public: /* ect */ void set_X_reference ( Parameter &T , int i ) { T.push_var( &node[i]->X ); } void set_Y_reference ( Parameter &T , int i ) { T.push_var( &node[i]->Y ); } void set_Z_reference ( Parameter &T , int i ) { T.push_var( &node[i]->Z ); } bool get_node_bool_X( int i ) { return node[i]->X.is_fixed; } // repeat for Y and Z }; class Parameter{ private: std::vector <VAR_TYPE*> var; public: /* ect */ }; int main(){ States S; Parameter P; /* Here I initialize and set S, and do other stuff */ // Now I assign components in States to Parameters for(int n=0 ; n<S.size_of_nodes() ; n++ ){ if ( S.get_node_bool_X(n)==true ){ S.set_X_reference ( P , n ); }; // repeat if statement for Y and Z }; /* Now P points selected to data in S, and I can * modify the contents of S through P */ return 0; }; Update The reason this issue cropped up is I am working with Fortran legacy code. To sum up this Fotran code - it's a numerical simulation of a flight vehicle. This code has a fairly rigid procedural framework one must work within, which comes with a pre-defined list of allowable Fortran types. The Fortran glue code can create an instance of a C++ object (in actuality, a reference from the perspective of Fortran), but is not aware what is contained in it (other means are used to extract C++ data into Fortran). The problem that I encountered is when a C++ module is dynamically linked to the Fortran glue code, C++ objects have to be initialized each instance the C++ code is called. This happens by virtue of how the Fortran template is defined. To avoid this cycle of re-initializing objects, I plan to use 'State' as a container class. The Fortran code allows a 'State' object, which has an arbitrary definition; but I plan to use it to harness all relevant information about the model. The idea is to use the Parameters class (which is exposed and updated by the Fortran code) to update variables in States.

    Read the article

  • Changing Value of Array Pointer When Passed to a Function

    - by ZAX
    I have a function which receives both the array, and a specific instance of the array. I try to change the specific instance of the array by accessing one of its members "color", but it does not actually change it, as can be seen by debugging (checking the value of color after function runs in the main program). I am hoping someone can help me to access this member and change it. Essentially I need the instance of the array I'm specifying to be passed by reference if nothing else, but I'm hoping there is an easier way to accomplish what I'm trying to do. Here's the structures: typedef struct adjEdge{ int vertex; struct adjEdge *next; } adjEdge; typedef struct vertex{ int sink; int source; int color; //0 will be white, 1 will be grey, 5 will be black int number; adjEdge *nextVertex; } vertex; And here is the function: void walk(vertex *vertexArray, vertex v, int source, maxPairing *head) { int i; adjEdge *traverse; int moveVertex; int sink; traverse = vertexArray[v.number-1].nextVertex; if(v.color != 5 && v.sink == 5) { sink = v.number; v.color = 5; addMaxPair(head, source, sink); } else { walk(vertexArray, vertexArray[traverse->vertex-1], source, head); } } In particular, v.color needs to be changed to a 5, that way later after recursion the if condition blocks it.

    Read the article

  • How to find distance between two geopoints in c using calculateDistance(const CWaypoint& wp)

    - by Harsha
    void getAllDataByPointer(string *pname,double *platitude, double *plongitude); void getAllDataByReference(string &pname,double &platitude, double &plongitude); double calculateDistance(const CWaypoint& wp); void print(int format); bool less(const CWaypoint& wp_right); CWaypoint add(const CWaypoint& wp_right); These are the functions I am using. I have the values as output but how to call the latitude values of two different cities so that I can use the following formula distance = ERADIUS * (acos(sin(latitude_1)*sin(latitude_2) + cos(latitude_1) * cos(latitude_2)*cos(longitude_2 - longitude_1)));

    Read the article

  • MOS Community rewards Ram Kasthuri w/ FREE OOW Pass!

    - by cwarticki
    Congratulations Ram Kasthuri on Receiving a Free Full Conference Pass to Oracle OpenWorld!  Thank you for helping other members through your participation in My Oracle Support Community My Oracle Support Community member Ram Kasthuri received a free Oracle OpenWorld Pass from the My Oracle Support Community in appreciation for his work in answering questions posted by other Community members. Ram, an independent consultant, is an Application Solution Architect with Canon. He has been a valued Oracle customer for over 13 years. Ram is an active member in several of the Oracle EBS communities. He has achieved the Expert Level of recognition through his active participation.   Ram described the value he receives from My Oracle Support Community when he said what “I like best about the communities is the vicarious learning from real business scenarios posted by other Community members. The questions are real opportunities to learn all things Oracle, and EBS especially.” Ram is one of those member's who answers more questions than he posts, so he must get a lot of that vicarious learning. Oracle Premier Support customers can get answers and learn from both peers who have faced similar situations and Oracle experts. Join us in My Oracle Support Community. Look for Ram this week at Oracle OpenWorld and join him in My Oracle Support Community when you return to work. And while you’re at Oracle OpenWorld, Oracle Customer Support Services invites you to expand your knowledge by meeting with Oracle Support experts. Learn more about our sessions and network opportunities today!

    Read the article

  • Should I pass link juice to my pages on other websites that are already high PR domains?

    - by huzzah
    I am starting a new website for a local business and have entries listed for it on places like urbanspoon, yelp, google+ local, etc. I am thinking of listing these citation sites on my business website to encourage visitors of my site to go and review the business on those sites. If I dofollow I will pass link juice to my page on that site, but doesn't that mean that the very very little PR juice I have will be leached away from me? Is it better to nofollow them?

    Read the article

  • How to execute a script as super user first checking the user and getting pass from askpass if not super user

    - by pahnin
    thers a similar question out there How can I determine whether a shellscript runs as root or not? I have the same doubt with different result Is it possible to, within the BASH script prior to everything being run, check if the script is being run as superuser, and if not, print a message saying You must be superuser to use this script, then subsequently get pass from the user using askpass or something like tht then execute the saem script as superuser?

    Read the article

< Previous Page | 43 44 45 46 47 48 49 50 51 52 53 54  | Next Page >