Search Results

Search found 1281 results on 52 pages for 'stl containers'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 16/52 | < Previous Page | 12 13 14 15 16 17 18 19 20 21 22 23  | Next Page >

  • Access Violation in std::pair

    - by sameer karjatkar
    I have an application which is trying to populate a pair. Out of nowhere the application crashes. The Windbg analysis on the crash dump suggests: PRIMARY_PROBLEM_CLASS: INVALID_POINTER_READ DEFAULT_BUCKET_ID: INVALID_POINTER_READ STACK_TEXT: 0389f1dc EPFilter32!std::vector<std::pair<unsigned int,unsigned int>,std::allocator<std::pair<unsigned int,unsigned int> > >::size+0xc INVALID_POINTER_READ_c0000005_Test.DLL!std::vector_std::pair_unsigned_int, unsigned_int_,std::allocator_std::pair_unsigned_int,unsigned_int_____::size Following is the code snap in the code where it fails: for (unsigned i1 = 0; i1 < size1; ++i1) { for (unsigned i2 = 0; i2 < size2; ++i2) { const branch_info& b1 = en1.m_branches[i1]; //Exception here :crash const branch_info& b2 = en2.m_branches[i2]; } } where branch_info is std::pair<unsigned int,unsigned int> and the en1.m_branches[i1] fetches me a pair value.

    Read the article

  • What is the best way to store incremental downloaded data?

    - by afriza
    Inspired by Chromium's sha1 class, I am thinking to store incrementally downloaded data using std::string // pseudo-code char buff[BUFF_SIZE]; std::string data; do { size = ReadInternetFileTo(buff,BUFF_SIZE); data.append(buff,size); } while (not_finished); Any foreseeable problems with this method or better way to do it?

    Read the article

  • Does std::multiset guarntee insertion order?

    - by Naveen
    I have a std::multiset which stores elements of class A. I have provided my own implementation of operator< for this class. My question is if I insert two equivalent objects into this multiset is their order guaranteed? For example, first I insert a object a1 into the set and then I insert an equivalent object a2 into this set. Can I expect the a1 to come before a2 when I iterate through the set? If no, is there any way to achieve this using multiset?

    Read the article

  • Make Map Key Sorted According To Insert Sequence

    - by Yan Cheng CHEOK
    Without help from additional container (like vector), is it possible that I can make map's key sorted same sequence as insertion sequence? #include <map> #include <iostream> using namespace std; int main() { map<const char*, int> m; m["c"] = 2; m["b"] = 2; m["a"] = 2; m["d"] = 2; for (map<const char*, int>::iterator begin = m.begin(); begin != m.end(); begin++) { // How can I get the loop sequence same as my insert sequence. // c, b, a, d std::cout << begin->first << std::endl; } getchar(); }

    Read the article

  • Weird behaviour with vector::erase and std::remove_if with end range different from vector.end()

    - by Edison Gustavo Muenz
    Hi, I need to remove elements from the middle of a std::vector. So I tried: struct IsEven { bool operator()(int ele) { return ele % 2 == 0; } }; int elements[] = {1, 2, 3, 4, 5, 6}; std::vector<int> ints(elements, elements+6); std::vector<int>::iterator it = std::remove_if(ints.begin() + 2, ints.begin() + 4, IsEven()); ints.erase(it, ints.end()); After this I would expect that the ints vector have: [1, 2, 3, 5, 6]. In the debugger of Visual studio 2008, after the std::remove_if line, the elements of ints are modified, I'm guessing I'm into some sort of undefined behaviour here. So, how do I remove elements from a Range of a vector?

    Read the article

  • Why do bind1st and bind2nd require constant function objects?

    - by rlbond
    So, I was writing a C++ program which would allow me to take control of the entire world. I was all done writing the final translation unit, but I got an error: error C3848: expression having type 'const `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>' would lose some const-volatile qualifiers in order to call 'void `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>::operator ()(const point::Point &,const int &)' with [ T=SideCounter, BinaryFunction=std::plus<int> ] c:\program files (x86)\microsoft visual studio 9.0\vc\include\functional(324) : while compiling class template member function 'void std::binder2nd<_Fn2>::operator ()(point::Point &) const' with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] c:\users\****\documents\visual studio 2008\projects\TAKE_OVER_THE_WORLD\grid_divider.cpp(361) : see reference to class template instantiation 'std::binder2nd<_Fn2>' being compiled with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] I looked in the specifications of binder2nd and there it was: it took a const AdaptibleBinaryFunction. So, not a big deal, I thought. I just used boost::bind instead, right? Wrong! Now my take-over-the-world program takes too long to compile (bind is used inside a template which is instantiated quite a lot)! At this rate, my nemesis is going to take over the world first! I can't let that happen -- he uses Java! So can someone tell me why this design decision was made? It seems like an odd decision. I guess I'll have to make some of the elements of my class mutable for now...

    Read the article

  • Using a map with set_intersection

    - by Robin Welch
    Not used set_intersection before, but I believe it will work with maps. I wrote the following example code but it doesn't give me what I'd expect: #include <map> #include <string> #include <iostream> #include <algorithm> using namespace std; struct Money { double amount; string currency; bool operator< ( const Money& rhs ) const { if ( amount != rhs.amount ) return ( amount < rhs.amount ); return ( currency < rhs.currency ); } }; int main( int argc, char* argv[] ) { Money mn[] = { { 2.32, "USD" }, { 2.76, "USD" }, { 4.30, "GBP" }, { 1.21, "GBP" }, { 1.37, "GBP" }, { 6.74, "GBP" }, { 2.55, "EUR" } }; typedef pair< int, Money > MoneyPair; typedef map< int, Money > MoneyMap; MoneyMap map1; map1.insert( MoneyPair( 1, mn[1] ) ); map1.insert( MoneyPair( 2, mn[2] ) ); map1.insert( MoneyPair( 3, mn[3] ) ); // (3) map1.insert( MoneyPair( 4, mn[4] ) ); // (4) MoneyMap map2; map1.insert( MoneyPair( 3, mn[3] ) ); // (3) map1.insert( MoneyPair( 4, mn[4] ) ); // (4) map1.insert( MoneyPair( 5, mn[5] ) ); map1.insert( MoneyPair( 6, mn[6] ) ); map1.insert( MoneyPair( 7, mn[7] ) ); MoneyMap out; MoneyMap::iterator out_itr( out.begin() ); set_intersection( map1.begin(), map1.end(), map2.begin(), map2.end(), inserter( out, out_itr ) ); cout << "intersection has " << out.size() << " elements." << endl; return 0; } Since the pair labelled (3) and (4) appear in both maps, I was expecting that I'd get 2 elements in the intersection, but no, I get: intersection has 0 elements. I'm sure this is something to do with the comparitor on the map / pair but can't figure it out.

    Read the article

  • I need programmatically way to perform fastest 'trans-wrap' of mov to mp4 on iPhone/iPad application

    - by user1307877
    I want to change the container of a .mov video files that I pick using  UIImagePickerController and compressed them via AVAssetExportSession with AVAssetExportPresetMediumQuality and  shouldOptimizeForNetworkUse = YES to .mp4 container. I need programmatically way/sample code to perform a fastest 'trans-wrap' on iPhone/iPad application I tried to set AVAssetExportSession.outputFileType property to AVFileTypeMPEG4 but it not supported and I got exception I tried to do this transform using AVAssetWriter by specifying fileType:AVFileTypeMPEG4, actually I got .mp4 output file, but it was not 'wrap-trans', the output file was  3x bigger than source, and the convert process took 128 sec for video with 60 sec duration. I need solution that will run quickly and will keep the file size  please help

    Read the article

  • std::list : get next element

    - by sheepsimulator
    I'm trying to build a string using data elements stored in a std::list, where I want commas placed only between the elements (ie, if elements are {A,B,C,D} in list, result string should be "A,B,C,D". This code does not work: typedef std::list< shared_ptr<EventDataItem> > DataItemList; // ... std::string Compose(DataItemList& dilList) { std::stringstream ssDataSegment; for(iterItems = dilList.begin(); iterItems = dilList.end(); iterItems++) { // Lookahead in list to see if next element is end if((iterItems + 1) == dilList.end()) { ssDataSegment << (*iterItems)->ToString(); } else { ssDataSegment << (*iterItems)->ToString() << ","; } } return ssDataSegment.str(); } How do I get at "the-next-item" in a std::list using an iterator? I would expect that it's a linked-list, why can't I get at the next item?

    Read the article

  • std::list or std::multimap

    - by Tamir
    Hey, I right now have a list of a struct that I made, I sort this list everytime I add a new object, using the std::list sort method. I want to know what would be faster, using a std::multimap for this or std::list, since I'm iterating the whole list every frame (I am making a game). I would like to hear your opinion, for what should I use for this incident.

    Read the article

  • Visual Studio C++ list iterator not decementable

    - by user69514
    I keep getting an error on visual studio that says list iterator not decrementable: line 256 My program works fine on Linux, but visual studio compiler throws this error. Dammit this is why I hate windows. Why can't the world run on Linux? Anyway, do you see what my problem is? #include <iostream> #include <fstream> #include <sstream> #include <list> using namespace std; int main(){ /** create the list **/ list<int> l; /** create input stream to read file **/ ifstream inputstream("numbers.txt"); /** read the numbers and add them to list **/ if( inputstream.is_open() ){ string line; istringstream instream; while( getline(inputstream, line) ){ instream.clear(); instream.str(line); /** get he five int's **/ int one, two, three, four, five; instream >> one >> two >> three >> four >> five; /** add them to the list **/ l.push_back(one); l.push_back(two); l.push_back(three); l.push_back(four); l.push_back(five); }//end while loop }//end if /** close the stream **/ inputstream.close(); /** display the list **/ cout << "List Read:" << endl; list<int>::iterator i; for( i=l.begin(); i != l.end(); ++i){ cout << *i << " "; } cout << endl << endl; /** now sort the list **/ l.sort(); /** display the list **/ cout << "Sorted List (head to tail):" << endl; for( i=l.begin(); i != l.end(); ++i){ cout << *i << " "; } cout << endl; list<int> lReversed; for(i=l.begin(); i != l.end(); ++i){ lReversed.push_front(*i); } cout << "Sorted List (tail to head):" << endl; for(i=lReversed.begin(); i!=lReversed.end(); ++i){ cout << *i << " "; } cout << endl << endl; /** remove first biggest element and display **/ l.pop_back(); cout << "List after removing first biggest element:" << endl; cout << "Sorted List (head to tail):" << endl; for( i=l.begin(); i != l.end(); ++i){ cout << *i << " "; } cout << endl; cout << "Sorted List (tail to head):" << endl; lReversed.pop_front(); for(i=lReversed.begin(); i!=lReversed.end(); ++i){ cout << *i << " "; } cout << endl << endl; /** remove second biggest element and display **/ l.pop_back(); cout << "List after removing second biggest element:" << endl; cout << "Sorted List (head to tail):" << endl; for( i=l.begin(); i != l.end(); ++i){ cout << *i << " "; } cout << endl; lReversed.pop_front(); cout << "Sorted List (tail to head):" << endl; for(i=lReversed.begin(); i!=lReversed.end(); ++i){ cout << *i << " "; } cout << endl << endl; /** remove third biggest element and display **/ l.pop_back(); cout << "List after removing third biggest element:" << endl; cout << "Sorted List (head to tail):" << endl; for( i=l.begin(); i != l.end(); ++i){ cout << *i << " "; } cout << endl; cout << "Sorted List (tail to head):" << endl; lReversed.pop_front(); for(i=lReversed.begin(); i!=lReversed.end(); ++i){ cout << *i << " "; } cout << endl << endl; /** create frequency table **/ const int biggest = 1000; //create array size of biggest element int arr[biggest]; //set everything to zero for(int j=0; j<biggest+1; j++){ arr[j] = 0; } //now update number of occurences for( i=l.begin(); i != l.end(); i++){ arr[*i]++; } //now print the frequency table. only print where occurences greater than zero cout << "Final list frequency table: " << endl; for(int j=0; j<biggest+1; j++){ if( arr[j] > 0 ){ cout << j << ": " << arr[j] << " occurences" << endl; } } return 0; }//end main

    Read the article

  • is back_insert_iterator<> safe to be passed by value?

    - by afriza
    I have a code that looks something like: struct Data { int value; }; class A { public: typedef std::deque<boost::shared_ptr<Data> > TList; std::back_insert_iterator<TList> GetInserter() { return std::back_inserter(m_List); } private: TList m_List; }; class AA { boost::scoped_ptr<A> m_a; public: AA() : m_a(new A()) {} std::back_insert_iterator<A::TList> GetDataInserter() { return m_a->GetInserter(); } }; class B { template<class OutIt> CopyInterestingDataTo(OutIt outIt) { // loop and check conditions for interesting data // for every `it` in a Container<Data*> // create a copy and store it for( ... it = ..; .. ; ..) if (...) { *outIt = OutIt::container_type::value_type(new Data(**it)); outIt++; // dummy } } void func() { AA aa; CopyInterestingDataTo(aa.GetInserter()); // aa.m_a->m_List is empty! } }; The problem is that A::m_List is always empty even after CopyInterestingDataTo() is called. However, if I debug and step into CopyInterestingDataTo(), the iterator does store the supposedly inserted data!

    Read the article

  • Compilation errors calling find_if using a functor

    - by Jim Wong
    We are having a bit of trouble using find_if to search a vector of pairs for an entry in which the first element of the pair matches a particular value. To make this work, we have defined a trivial functor whose operator() takes a pair as input and compares the first entry against a string. Unfortunately, when we actually add a call to find_if using an instance of our functor constructed using a temporary string value, the compiler produces a raft of error messages. Oddly (to me, anyway), if we replace the temporary with a string that we've created on the stack, things seem to work. Here's what the code (including both versions) looks like: typedef std::pair<std::string, std::string> MyPair; typedef std::vector<MyPair> MyVector; struct MyFunctor: std::unary_function <const MyPair&, bool> { explicit MyFunctor(const std::string& val) : m_val(val) {} bool operator() (const MyPair& p) { return p.first == m_val; } const std::string m_val; }; bool f(const char* s) { MyFunctor f(std::string(s)); // ERROR // std::string str(s); // MyFunctor f(str); // OK MyVector vec; MyVector::const_iterator i = std::find_if(vec.begin(), vec.end(), f); return i != vec.end(); } And here's what the most interesting error message looks like: /usr/include/c++/4.2.1/bits/stl_algo.h:260: error: conversion from ‘std::pair, std::allocator , std::basic_string, std::allocator ’ to non-scalar type ‘std::string’ requested Because we have a workaround, we're mostly curious as to why the first form causes problems. I'm sure we're missing something, but we haven't been able to figure out what it is.

    Read the article

  • Trouble passing a template function as an argument to another function in C++

    - by Darel
    Source of the problem -Accelerated C++, problem 8-5 I've written a small program that examines lines of string input, and tallies the number of times a word appears on a given line. The following code accomplishes this: #include <map> #include <iostream> #include <string> #include <vector> #include <list> #include <cctype> #include <iterator> using std::vector; using std::string; using std::cin; using std::cout; using std::endl; using std::getline; using std::istream; using std::string; using std::list; using std::map; using std::isspace; using std::ostream_iterator; using std::allocator; inline void keep_window_open() { cin.clear(); cout << "Please enter EOF to exit\n"; char ch; cin >> ch; return; } template <class Out> void split(const string& s, Out os) { vector<string> ret; typedef string::size_type string_size; string_size i = 0; // invariant: we have processed characters `['original value of `i', `i)' while (i != s.size()) { // ignore leading blanks // invariant: characters in range `['original `i', current `i)' are all spaces while (i != s.size() && isspace(s[i])) ++i; // find end of next word string_size j = i; // invariant: none of the characters in range `['original `j', current `j)' is a space while (j != s.size() && !isspace(s[j])) ++j; // if we found some nonwhitespace characters if (i != j) { // copy from `s' starting at `i' and taking `j' `\-' `i' chars *os++ = (s.substr(i, j - i)); i = j; } } } // find all the lines that refer to each word in the input map<string, vector<int> > xref(istream& in) // works // now try to pass the template function as an argument to function - what do i put for templated type? //map<string, vector<int> > xref(istream& in, void find_words(vector<string, typedef Out) = split) #LINE 1# { string line; int line_number = 0; map<string, vector<int> > ret; // read the next line while (getline(in, line)) { ++line_number; // break the input line into words vector<string> words; // works // #LINE 2# split(line, back_inserter(words)); // #LINE 3# //find_words(line, back_inserter(words)); // #LINE 4# attempting to use find_words as an argument to function // remember that each word occurs on the current line for (vector<string>::const_iterator it = words.begin(); it != words.end(); ++it) ret[*it].push_back(line_number); } return ret; } int main() { cout << endl << "Enter lines of text, followed by EOF (^Z):" << endl; // call `xref' using `split' by default map<string, vector<int> > ret = xref(cin); // write the results for (map<string, vector<int> >::const_iterator it = ret.begin(); it != ret.end(); ++it) { // write the word cout << it->first << " occurs on line(s): "; // followed by one or more line numbers vector<int>::const_iterator line_it = it->second.begin(); cout << *line_it; // write the first line number ++line_it; // write the rest of the line numbers, if any while (line_it != it->second.end()) { cout << ", " << *line_it; ++line_it; } // write a new line to separate each word from the next cout << endl; } keep_window_open(); return 0; } As you can see, the split function is a template function to handle various types of output iterators as desired. My problem comes when I try to generalize the xref function by passing in the templated split function as an argument. I can't seem to get the type correct. So my question is, can you pass a template function to another function as an argument, and if so, do you have to declare all types before passing it? Or can the compiler infer the types from the way the templated function is used in the body? To demonstrate the errors I get, comment out the existing xref function header, and uncomment the alternate header I'm trying to get working (just below the following commment line.) Also comment the lines tagged LINE 2 and LINE 3 and uncomment LINE 4, which is attempting to use the argument find_words (which defaults to split.) Thanks for any feedback!

    Read the article

  • asking the container to notify your application whenever a session is about to timeout in Java

    - by user136101
    Which method(s) can be used to ask the container to notify your application whenever a session is about to timeout?(choose all that apply) A. HttpSessionListener.sessionDestroyed -- correct B. HttpSessionBindingListener.valueBound C. HttpSessionBindingListener.valueUnbound -- correct this is kind of round-about but if you have an attribute class this is a way to be informed of a timeout D. HttpSessionBindingEvent.sessionDestroyed -- no such method E. HttpSessionAttributeListener.attributeRemoved -- removing an attribute isn’t tightly associated with a session timeout F. HttpSessionActivationListener.sessionWillPassivate -- session passivation is different than timeout I agree with option A. 1) But C is doubtful How can value unbound be tightly coupled with session timeout.It is just the callback method when an attribute gets removed. 2) and if C is correct, E should also be correct. HttpSessionAttributeListener is just a class that wants to know when any type of attribute has been added, removed, or replaced in a session. It is implemented by any class. HttpSessionBindingListener exists so that the attribute itself can find out when it has been added to or removed from a session and the attribute class must implement this interface to achieve it. Any ideas…

    Read the article

  • Why can't I access a const vector with iterator?

    - by tsubasa
    My example is as below. I found out the problem is with "const" in function void test's parameter. I don't know why the compiler does not allow. Could anybody tell me? Thanks. vector<int> p; void test(const vector<int> &blah) { vector<int>::iterator it; for (it=blah.begin(); it!=blah.end(); it++) { cout<<*it<<" "; } } int main() { p.push_back(1); p.push_back(2); p.push_back(3); test(p); return 0; }

    Read the article

  • Providing less than operator for one element of a pair

    - by Koszalek Opalek
    What would be the most elegant way too fix the following code: #include <vector> #include <map> #include <set> using namespace std; typedef map< int, int > row_t; typedef vector< row_t > board_t; typedef row_t::iterator area_t; bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; int main( int argc, char* argv[] ) { int row_num; area_t it; set< pair< int, area_t > > queue; queue.insert( make_pair( row_num, it ) ); // does not compile }; One way to fix it is moving the definition of less< to namespace std (I know, you are not supposed to do it.) namespace std { bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; }; Another obvious solution is defining less than< for pair< int, area_t but I'd like to avoid that and be able to define the operator only for the one element of the pair where it is not defined.

    Read the article

  • How to use a "vector of vector" ?

    - by Mike Dooley
    Hi! I allready searched on the web for it but I didn't get satisfying results. I want to create something like vector< vector<int*> > test_vector; How do i fill this vector of vector? How to acces it's members? Maybe someone knows some nice tutorials on the web? kind regards mikey

    Read the article

  • C++ iterators, default initialization and what to use as an uninitialized sentinel.

    - by Hassan Syed
    The Context I have a custom template container class put together from a map and vector. The map resolves a string to an ordinal, and the vector resolves an ordinal (only an initial string to ordinal lookup is done, future references are to the vector) to the entry. The entries are modified intrusively to contain a a bool "assigned" and an iterator_type which is a const_iterator to the container class's map. My container class will use RCF's serialization code (which models boost::serialization) to serialize my container classes to nodes in a network. Serializing iterator's is not possible, or a can of worms, and I can easily regenerate them onces the vectors and maps are serialized on the remote site. The Question I need to default initialize, and be able to test that the iterator has not been assigned to (if it is assigned it is valid, if not it is invalid). Since map iterators are not invalidated upon operations performed on it (unless of course items are removed :D) am I to assume that map<x,y>::end() is a valid sentinel (regardless of the state of the map -- i.e., it could be empty) to initialize to ? I will always have access to the parent map, I'm just unsure wheather end() is the same as the map contents change. I don't want to use another level of indirection (--i.e., boost::optional) to achieve my goal, I'd rather forego compiler checks to correct logic, but it would be nice if I didn't need to. Misc This question exists, but most of its content seems non-sense. Assigning a NULL to an iterator is invalid according to g++ and clang++. This is another similar question, but it focuses on the common use-cases of iterators, which generally tends to be using the iterator to iterate, ofcourse in this use-case the state of the container isn't meant to change whilst iteration is going on.

    Read the article

  • Vector [] vs copying

    - by sak
    What is faster and/or generally better? vector<myType> myVec; int i; myType current; for( i = 0; i < 1000000; i ++ ) { current = myVec[ i ]; doSomethingWith( current ); doAlotMoreWith( current ); messAroundWith( current ); checkSomeValuesOf( current ); } or vector<myType> myVec; int i; for( i = 0; i < 1000000; i ++ ) { doSomethingWith( myVec[ i ] ); doAlotMoreWith( myVec[ i ] ); messAroundWith( myVec[ i ] ); checkSomeValuesOf( myVec[ i ] ); } I'm currently using the first solution. There are really millions of calls per second and every single bit comparison/move is performance-problematic.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 12 13 14 15 16 17 18 19 20 21 22 23  | Next Page >