Search Results

Search found 10366 results on 415 pages for 'const char pointer'.

Page 309/415 | < Previous Page | 305 306 307 308 309 310 311 312 313 314 315 316  | Next Page >

• Understanding c++ block of code

  - by kotoko

  I was given a c++ main and have to code it so it works. I am having some trouble understanding the code as I am a bit new to cpp. Here is the code int main(int argc, char *argv[]) { Class::setAtribute("string"); Class(Class::CONSTANT) << "starting up..."; } Some questions: How can the first line work with no variables? Is it static? The second line is really strange for me, what I can make out is a Constructor that takes in a class constante and then prints it out somehow? If someone could explain me this bit of code it would be great! Thanks in advance.

  Read the article

• SQL SELECT using in() but excluding others.

  - by Pickledegg

  I have a table called 'countries' linked to another table 'networks' with a many to many relationship: countries countries_networks networks +-------------+----------+ +-------------+----------+ +-------------+---------------+ | Field | Type | | Field | Type | | Field | Type | +-------------+----------+ +-------------+----------+ +-------------+---------------+ | id | int(11) | | id | int(11) | | id | int(11) | | countryName | char(35) | | country_id | int(11) | | name | varchar(100) | +-------------+----------+ | network_id | int(11) | | description | varchar(255) | To retrieve all countries that have a network_id of 6 & 7, I just do the following: ( I could go further to use the networks.name but I know the countries_networks.network_id so i just use those to reduce SQL.) SELECT DISTINCT countryName FROM countries AS Country INNER JOIN countries_networks AS n ON Country.id = n.country_id WHERE n.network_id IN (6,7) This is fine, but I then want to retrieve the countries with a network_id of JUST 8, and no others. I'ver tried the following but its still returning networks with 6 & 7 in. Is it something to do with my JOIN? SELECT DISTINCT countryName FROM countries AS Country INNER JOIN countries_networks AS n ON Country.id = n.country_id WHERE n.network_id IN (8) AND n.network_id not IN(6,7) Thanks.

  Read the article

• Can anyone tell me were I am making mistake in the snippet

  - by Solitaire

  public partial class Form1 : Form { [DllImport("coredll.dll")] static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong); const int GWL_WNDPROC = -4; public delegate int WindProc(IntPtr hWnd, uint msg, long Wparam, long lparam); public Form1() { InitializeComponent(); WindProc SampleProc = new WindProc (SubclassWndProc); SetWindowLong(this .Handle , GWL_WNDPROC, SampleProc.Method .MethodHandle.Value.ToInt32()); } public int SubclassWndProc(IntPtr hwnd, uint msg, long Wparam, long lparam) { return 1; } Here is the sample which i was trying to take the window procedure of a form, this is how i do in C++ i get the windwproc easlily if i try the same in C# .net 3.5 i am unable to get the window proc,, after calling SetWindowLong API application hangs and it pops up some dont send report... i have read this is the way to get the window proc.. please let me know were i am making mistake...

  Read the article

• memset on array of structures in C++

  - by garry

  I have another memset question. It appears as if the code I am editing may have some issues (or it's not done the same way in different files) A::LRM las[9]; //A and LRM are both structures with BOOLS and INTS memset(&las, 0, sizeof(las)); typedef Sec SecArray[16]; SecArray rad_array; memset(rad_array, 0, sizeof(SecArray)); The second example appears to be correct because rad_array is the same as the first position in the array. Then the sizeof(SecArray)) would make sense. The first one doesn't seem correct to me. All structs are just BOOLs and INTS nothing dynamic in them. My understanding from my other post about memset was that it followed this format. memset("pointer to object", "what to set it to", "size of object") Can anyone tell me what exactly is going on here if I am incorrect with my theory.

  Read the article

• C++ iterators & loop optimization

  - by Quantum7

  I see a lot of c++ code that looks like this: for( const_iterator it = list.begin(), const_iterator ite = list.end(); it != ite; ++it) As opposed to the more concise version: for( const_iterator it = list.begin(); it != list.end(); ++it) Will there be any difference in speed between these two conventions? Naively the first will be slightly faster since list.end() is only called once. But since the iterator is const, it seems like the compiler will pull this test out of the loop, generating equivalent assembly for both.

  Read the article

• C - add elements to struct by define

  - by CodeStepper

  I have a problem. I'm trying to add struct elements by previously defined constant. This is sample code (OpenGL+WinAPI) #define ENGINE_STRUCT \ HGLRC RenderingContext;\ HDC DeviceContext; And then: typedef struct SWINDOW { ENGINE_STRUCT HWND Handle; HINSTANCE Instance; CHAR* ClassName; BOOL Fullscreen; BOOL Active; MSG Message; } WINDOW; Is this possible? Thanks in advance.

  Read the article

• Why do virtual memory addresses for linux binaries start at 0x8048000?

  - by muteW

  Disassembling an ELF binary on a Ubuntu x86 system I couldn't help but notice that the code(.text) section starts from the virtual address 0x8048000 and all lower memory addresses seem to be unused. This seems to be rather wasteful and all Google turns up is either folklore involving STACK_TOP or protection against null-pointer dereferences. The latter case looks like it can be fixed by using a single page instead of leaving a 128MB gap. So my question is this - is there a definitive answer to why the layout has been fixed to these values or is it just an arbitrary choice?

  Read the article

• why it is up to the compiler to decide what value to assign when assigning an out-of-range value to

  - by Allopen

  in C++ Primer 4th edition 2.1.1, it says "when assigning an out-of-range value to a signed type, it is up to the compiler to decide what value to assign". I can't understand it. I mean, if you have code like "char 5 = 299", certainly the compiler will generate asm code like "mov BYTE PTR _sc$[ebp], 43"(VC) or "movb $43, -2(%ebp)"(gcc+mingw), it IS decided by the compiler. but what if we assign a value that is given by the user input? like, via command line? and the asm code generated will be "movb %al, -1(%ebp)"(gcc+mingw) and " mov cl, BYTE PTR _i$[ebp] mov BYTE PTR _sc$[ebp], cl "(VC), so now how can compiler decide what will happen? I think now it is decided by the CPU. Can you give me a clear explanation?

  Read the article

• View is moved 3 pixels

  - by Jakub

  Hello, In my app I move the table view (in order to make the text fields visible when the keyboard appears). The view is looks following: This is the code I use for resizing the view and moving it up: static const NSUInteger navBarHeight = 44; CGRect appFrame = [[UIScreen mainScreen] applicationFrame]; tableView.frame = CGRectMake(0, navBarHeight, appFrame.size.width, appFrame.size.height-navBarHeight-216); //216 for the keyboard NSIndexPath *indPath = [self getIndexPathForTextField:textField]; //get the field the view should scroll to [tableView scrollToRowAtIndexPath:indPath atScrollPosition:UITableViewScrollPositionMiddle animated:YES]; The problem is that when the view is moved up it also moves 3 pixels into right direction (it is hard to see the difference in the screenshot, but it is visible when the animation is on and I measured the difference with PixelStick tool). Here it is how it looks after the move: My analysis shows that scrolling the table does not influence the move to the right. Any ideas what is wrong in the code above that makes the view move to the right?

  Read the article

• DataSet binding problem

  - by Shaine

  I've got in-memory dataset with some table defined and I populate this table in a following way: for(...) ds.Fields.AddFieldsRow(++j, 0, heading, "Char", "", "", "Input", 0, "","",""); On the GUI I've got DataGridView bound to that table inside TabControl (bound through BindingSource). Very strange thing is happening: if I open tab pane with this grid and populate table with some data then I see changes in grid. On the other side if I'm at other tab, populate table, and then switch to tab with grid I've got following exception: "DataMember property 'Fields' cannot be found on the DataSource". In similar way I've got 2 tab panes with grid in each that are bound to the same datatable using different datasources and I open one of them, populate, see the changes, then switch to second tab and get crash. What am I missing?

  Read the article

• SQL tables using VARCHAR with UTF8 (with respect to multi byte character length)

  - by Elius

  Like in Oracle VARCHAR( 60 CHAR ) I would like to specify a varchar field with variable length depending on the inserted characters. for example: create table X (text varchar(3)) insert into X (text) VALUES ('äöü') Should be possible (with UTF8 as the default charset of the database). On DB2 I got this Error: DB2 SQL Error: SQLCODE=-302, SQLSTATE=22001 (Character data, right truncation occurred; for example, an update or insert value is a string that is too long for the column, or a datetime value cannot be assigned to a host variable, because it is too small.) I'm looking for solutions for DB2, MsSql, MySql, Hypersonic.

  Read the article

• How to return a copy of the data in C++

  - by Josh Curren

  I am trying to return a new copy of the data in a C++ Template class. The following code is getting this error: invalid conversion from ‘int*’ to ‘int’. If I remove the new T then I am not returning a copy of the data but a pointer to it. template<class T> T OrderedList<T>::get( int k ) { Node<T>* n = list; for( int i = 0; i < k; i++ ) { n=n->get_link(); } return new T( n->get_data() ); // This line is getting the error ********** }

  Read the article

• Looking at the C++ new[] cookie. How portable is this code?

  - by carleeto

  I came up with this as a quick solution to a debugging problem - I have the pointer variable and its type, I know it points to an array of objects allocated on the heap, but I don't know how many. So I wrote this function to look at the cookie that stores the number of bytes when memory is allocated on the heap. template< typename T > int num_allocated_items( T *p ) { return *((int*)p-4)/sizeof(T); } //test #include <iostream> int main( int argc, char *argv[] ) { using std::cout; using std::endl; typedef long double testtype; testtype *p = new testtype[ 45 ]; //prints 45 std::cout<<"num allocated = "<<num_allocated_items<testtype>(p)<<std::endl; delete[] p; return 0; } I'd like to know just how portable this code is.

  Read the article

• Passing arguments to Shared Function - C

  - by SpyrosR

  I have used dlopen to load an object and dlsym to get a function pointer to a shared object function. Everything works fine. I have tested it calling then the shared function which (for now) only prints and it works-prints fine in the main program calling it. Now I want to pass two arguments to this function. An int and a char * .Can anyone help me understand how can I pass arguments to a shared function? I have searched in the web but I cannot understand how it works.

  Read the article

• C++ inheritance question

  - by user233973

  Hi guys, I have a C++ inheritance related question. I have a set of classes like this (I have not given the complete class structure coz I am lazy :) ). I want to access chiComponent class public methods using com pointer. How should I go about it? Note that I am having to change the object which "com" is pointing to in a lot of places. So I do not think I can have another chiComponent *ccom = <some_cast> com; ccom.chiComponentMethod() How should I go about it? class Component{ }; class chiComponent : public Component { public: void chiComponentMethod() { cout << "Hi! Chi component function called!!"; } } class parent { protected: Component *com; }; class child : public parent{ public: child() { com = new chiComponent(); } } Regards Arun

  Read the article

• [C] Read line from file without knowing the line length.

  - by ryyst

  Hi, I want to read in a file line by line, without knowing the line length before. Here's what I got so far: int ch = getc(file); int length = 0; char buffer[4095]; while (ch != '\n' && ch != EOF) { ch = getc(file); buffer[length] = ch; length++; } printf("Line length: %d characters.", length); I can now figure out the line length, but only for lines that are shorter than 4095 characters. Is there a better way to do this (I already used fgets() but got told it wasn't the best way)? --Ry

  Read the article

• How do I change the class of an object to a subclass of its current class in C++?

  - by Jared P

  I have an array of pointers to a base class, so that I can make those pointers point to (different) subclasses of the base class, but still interact with them. (really only a couple of methods which I made virtual and overloaded) I'm wondering if I can avoid using the pointers, and instead just make an array of the base class, but have some way to set the class to the subclass of my choosing. I know there must be something there specifying the class, as it needs to use that to look up the function pointer for virtual methods. By the way, the subclasses all have the same ivars and layout. Note: the design is actually based on using a template argument instead of a variable, due to performance increases, so really the abstract base class is just the interface for the subclasses, which are all the same except for their compiled code. Thanks

  Read the article

• std::out_of_range error?

  - by vette982

  I'm dealing with a file with a linked list of lines with each node looking like this: struct TextLine{ //The actual text string text; //The line number of the document int line_num; //A pointer to the next line TextLine * next; }; and I'm writing a function that adds spaces at the beginning of the lines found in the variable text, by calling functions like linelist_ptr->text.insert(0,1,'\t'); The program compiles, but when I run it I get this error: terminate called after throwing an instance of 'std::out_of_range' what(): basic_string::at Aborted Any ideas?

  Read the article

• Iterating through std queue

  - by Ockonal

  Hi, I'm trying to use BOOST_FOREACH for iterating through the std::queue. But there isn't iterators in that class cause I have an error: std::queue<std::string> someList; BOOST_FOREACH(std::string temp, someList) { std::cout << temp; } >no matching function for call to begin(...) >no type named ‘iterator’ in ‘class std::queue<std::basic_string<char> >’ I need in structure like: the first comes, the first goes away.

  Read the article

• Is call to function object inlined?

  - by dehmann

  In the following code, Foo::add calls a function via a function object: struct Plus { inline int operator()(int x, int y) const { return x + y; } }; template<class Fct> struct Foo { Fct fct; Foo(Fct f) : fct(f) {} inline int add(int x, int y) { return fct(x,y); // same efficiency adding directly? } }; Is this the same efficiency as calling x+y directly in Foo::add? In other words, does the compiler typically directly replace fct(x,y) with the actual call, inlining the code, when compiling with optimizations enabled?

  Read the article

• How to retrieve all keys (or values) from a std::map?

  - by Owen

  This is one of the possible ways I come out: struct RetrieveKey { template <typename T> typename T::first_type operator()(T keyValuePair) const { return keyValuePair.first; } }; map<int, int> m; vector<int> keys; // Retrieve all keys transform(m.begin(), m.end(), back_inserter(keys), RetrieveKey()); // Dump all keys copy(keys.begin(), keys.end(), ostream_iterator<int>(cout, "\n")); Of course, we can also retrieve all values from the map by defining another functor RetrieveValues. Is there any other way to achieve this easily? (I'm always wondering why std::map does not include a member function for us to do so.)

  Read the article

• MySQLi String comparisons using keys

  - by asdasd

  I have a table with lets say 2 columns. id number, and value. Value is a string (var char). Lets say i have a number x, and a list of numbers a1, a2, a3, a4, a5..... where x is not in the list. All of these numbers correspond to a unique row in the table. I want to know if the string value for x in the table is contained in one of the string values for any table entry for a1, a2, a3, a4... Lets say i have these rows: x, aaa a1, bbb a2, ccc a3, ddd a4, aaabbbcc then i want somehow a confirmation that yes, the value for x is included in one of the values in my list of numbers (a4 contains x). I know i can do this in a couple queries and shove it down some PHP and get my answer. But can i do this with one query?

  Read the article

• Event handling C# / Registering a callback

  - by Jeff Dahmer

  Events can only return void and recieve object sender/eventargs right? If so then craptastic.... how can I pass a function pointer to another obj, like: public bool ACallBackFunc(int n) { return n > 0; } public void RegisterCallback(Something s) { s.GiveCallBack(this.ACallBackFunc); } Something::GiveCallBack(Action? funcPtr) I tried using Action, but I need it to return some value and Actions can only return void. Also, we do not know what kind of a callback we will be recieving; it could return anything and have any params! Reflection will have to be used somehow I reckon.

  Read the article

• Oracle spatial search within distance

  - by KA_lin

  I have the following table Cities: ID(int),City(char),latitude(float),longitude(float). Now based on a user`s longitude(ex:44.8) and latitude(ex:46.3) I want to search for all the cities near him within 100 miles/KM. I have found some examples but don`t know how to adapt them to my case select * from GEO.Cities a where SDO_WITHIN_DISTANCE([I don`t know], MDSYS.SDO_GEOMETRY(2001, 8307, MDSYS.SDO_POINT_TYPE(44.8,46.3, NULL) ,NULL, NULL), 'distance = 1000') = 'TRUE'; Any help would be appreciated. P.S: If it is possible to have the distance and to be sorted P.P.S: I want to do it in this way due to performance issues, I have done this in this way http://www.scribd.com/doc/2569355/Geo-Distance-Search-with-MySQL but it takes too long...

  Read the article

• Infinite gtk warnings when I right click on the icon

  - by Runner

  From this tuto: #include <gtk/gtk.h> int main( int argc, char *argv[]) { GtkWidget *window; gtk_init(&argc, &argv); window = gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_widget_show(window); gtk_main(); return 0; } I run the executable and right click on the icon,then infinite warnings(the same) reported: GLib-WARNING **: g_main_context_check() called recursively from within a source's check() or prepare() member. Anyone knows how to fix this warning?

  Read the article

< Previous Page | 305 306 307 308 309 310 311 312 313 314 315 316  | Next Page >