Search Results

Search found 1006 results on 41 pages for 'istream iterator'.

Page 5/41 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • Temporary non-const istream reference in constructor (C++)

    - by Christopher Bruns
    It seems that a constructor that takes a non-const reference to an istream cannot be constructed with a temporary value in C++. #include <iostream> #include <sstream> using namespace std; class Bar { public: explicit Bar(std::istream& is) {} }; int main() { istringstream stream1("bar1"); Bar bar1(stream1); // OK on all platforms // compile error on linux, Mac gcc; OK on Windows MSVC Bar bar2(istringstream("bar2")); return 0; } This compiles fine with MSVC, but not with gcc. Using gcc I get a compile error: g++ test.cpp -o test test.cpp: In function ‘int main()’: test.cpp:18: error: no matching function for call to ‘Bar::Bar(std::istringstream)’ test.cpp:9: note: candidates are: Bar::Bar(std::istream&) test.cpp:7: note: Bar::Bar(const Bar&) Is there something philosophically wrong with the second way (bar2) of constructing a Bar object? It looks nicer to me, and does not require that stream1 variable that is only needed for a moment.

    Read the article

  • build error with boost spirit grammar (boost 1.43 and g++ 4.4.1)

    - by lurscher
    I'm having issues getting a small spirit/qi grammar to compile. The build stack trace is fugly enought to not make any sense to me (despite some assertion_failed i could notice in there but that didn't brought much information) the input grammar header: inputGrammar.h #include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_fusion.hpp> #include <boost/spirit/include/phoenix_stl.hpp> #include <boost/fusion/include/adapt_struct.hpp> #include <boost/variant/recursive_variant.hpp> #include <boost/foreach.hpp> #include <iostream> #include <fstream> #include <string> #include <vector> namespace sp = boost::spirit; namespace qi = boost::spirit::qi; using namespace boost::spirit::ascii; //using namespace boost::spirit::arg_names; namespace fusion = boost::fusion; namespace phoenix = boost::phoenix; using phoenix::at_c; using phoenix::push_back; template< typename Iterator , typename ExpressionAST > struct InputGrammar : qi::grammar<Iterator, ExpressionAST(), space_type> { InputGrammar() : InputGrammar::base_type( block ) { tag = sp::lexeme[+(alpha) [sp::_val += sp::_1]];//[+(char_ - '<') [_val += _1]]; block = sp::lit("block") [ at_c<0>(sp::_val) = sp::_1] >> "(" >> *instruction[ push_back( at_c<1>(sp::_val) , sp::_1 ) ] >> ")"; command = tag [ at_c<0>(sp::_val) = sp::_1] >> "(" >> *instruction [ push_back( at_c<1>(sp::_val) , sp::_1 )] >> ")"; instruction = ( command | tag ) [sp::_val = sp::_1]; } qi::rule< Iterator , std::string() , space_type > tag; qi::rule< Iterator , ExpressionAST() , space_type > block; qi::rule< Iterator , ExpressionAST() , space_type > function_def; qi::rule< Iterator , ExpressionAST() , space_type > command; qi::rule< Iterator , ExpressionAST() , space_type > instruction; }; the test build program: i seems the build fails at qi::phrase_parse, i am using boost 1.43 and g++ 4.4.1 #include <iostream> #include <string> #include <vector> using namespace std; //my grammar #include <InputGrammar.h> struct MockExpressionNode { std::string name; std::vector< MockExpressionNode > operands; typedef std::vector< MockExpressionNode >::iterator iterator; typedef std::vector< MockExpressionNode >::const_iterator const_iterator; iterator begin() { return operands.begin(); } const_iterator begin() const { return operands.begin(); } iterator end() { return operands.end(); } const_iterator end() const { return operands.end(); } bool is_leaf() const { return ( operands.begin() == operands.end() ); } }; BOOST_FUSION_ADAPT_STRUCT( MockExpressionNode, (std::string, name) (std::vector<MockExpressionNode>, operands) ) int const tabsize = 4; void tab(int indent) { for (int i = 0; i < indent; ++i) std::cout << ' '; } template< typename ExpressionNode > struct ExpressionNodePrinter { ExpressionNodePrinter(int indent = 0) : indent(indent) { } void operator()(ExpressionNode const& node) const { cout << " tag: " << node.name << endl; for (int i=0 ; i < node.operands.size() ; i++ ) { tab( indent ); cout << " arg "<<i<<": "; ExpressionNodePrinter(indent + 2)( node.operands[i]); cout << endl; } } int indent; }; int test() { MockExpressionNode root; InputGrammar< string::const_iterator , MockExpressionNode > g(); std::string litA = "litA"; std::string litB = "litB"; std::string litC = "litC"; std::string litD = "litD"; std::string litE = "litE"; std::string litF = "litF"; std::string source = litA+"( "+litB+" ,"+litC+" , "+ litD+" ( "+litE+", "+litF+" ) "+ " )"; string::const_iterator iter = source.begin(); string::const_iterator end = source.end(); bool r = qi::phrase_parse( iter , end , g , root , space ); ExpressionNodePrinter< MockExpressionNode > np; np( root ); }; int main() { test(); } finally, the build error is the following: /usr/bin/make -f nbproject/Makefile-linux_amd64_devel.mk SUBPROJECTS= .build-conf make[1]: se ingresa al directorio `/home/mineq/NetBeansProjects/InputParserTests' /usr/bin/make -f nbproject/Makefile-linux_amd64_devel.mk dist/linux_amd64_devel/GNU-Linux-x86/vpuinputparsertests make[2]: se ingresa al directorio `/home/mineq/NetBeansProjects/InputParserTests' mkdir -p build/linux_amd64_devel/GNU-Linux-x86 rm -f build/linux_amd64_devel/GNU-Linux-x86/tests_main.o.d g++ `llvm-config --cxxflags` `pkg-config --cflags unittest-cpp` `pkg-config --cflags boost-1.43` `pkg-config --cflags boost-coroutines` -c -g -I../InputParser -MMD -MP -MF build/linux_amd64_devel/GNU-Linux-x86/tests_main.o.d -o build/linux_amd64_devel/GNU-Linux-x86/tests_main.o tests_main.cpp from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/auto.hpp:16, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi.hpp:15, from /home/mineq/third_party/boost_1_43_0/boost/spirit/include/qi.hpp:16, from ../InputParser/InputGrammar.h:12, from tests_main.cpp:14: /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp: In function ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]’: In file included from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/detail/parse_auto.hpp:14, /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:125: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::spirit::ascii::space_type]’ tests_main.cpp:206: instantiated from here /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:99: error: no matching function for call to ‘assertion_failed(mpl_::failed************ (boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]::error_invalid_expression::************)(InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode> (*)()))’ /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:125: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::spirit::ascii::space_type]’ tests_main.cpp:206: instantiated from here /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:100: error: no matching function for call to ‘assertion_failed(mpl_::failed************ (boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]::error_invalid_expression::************)(MockExpressionNode))’ from /home/mineq/third_party/boost_1_43_0/boost/proto/proto.hpp:12, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/support/meta_compiler.hpp:17, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/meta_compiler.hpp:14, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/action/action.hpp:14, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/action.hpp:14, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi.hpp:14, from /home/mineq/third_party/boost_1_43_0/boost/spirit/include/qi.hpp:16, from ../InputParser/InputGrammar.h:12, from tests_main.cpp:14: /home/mineq/third_party/boost_1_43_0/boost/proto/detail/expr0.hpp: At global scope: /home/mineq/third_party/boost_1_43_0/boost/proto/proto_fwd.hpp: In instantiation of ‘boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>()>, 0l>’: In file included from /home/mineq/third_party/boost_1_43_0/boost/proto/core.hpp:13, /home/mineq/third_party/boost_1_43_0/boost/utility/enable_if.hpp:59: instantiated from ‘boost::disable_if<boost::proto::result_of::is_expr<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>()>, 0l>, void>, void>’ /home/mineq/third_party/boost_1_43_0/boost/spirit/home/support/meta_compiler.hpp:200: instantiated from ‘boost::spirit::result_of::compile<boost::spirit::qi::domain, InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), boost::fusion::unused_type, void>’ /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:107: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]’ /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:125: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::spirit::ascii::space_type]’ tests_main.cpp:206: instantiated from here /home/mineq/third_party/boost_1_43_0/boost/proto/detail/expr0.hpp:64: error: field ‘boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>()>, 0l>::child0’ invalidly declared function type from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/auto.hpp:16, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi.hpp:15, from /home/mineq/third_party/boost_1_43_0/boost/spirit/include/qi.hpp:16, from ../InputParser/InputGrammar.h:12, from tests_main.cpp:14: /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp: In function ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]’: In file included from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/detail/parse_auto.hpp:14, /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:125: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::spirit::ascii::space_type]’ tests_main.cpp:206: instantiated from here /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:107: error: request for member ‘parse’ in ‘boost::spirit::compile [with Domain = boost::spirit::qi::domain, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>()](((InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode> (&)())((InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode> (*)())expr)))’, which is of non-class type ‘InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>()’ from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/auto.hpp:15, from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi.hpp:15, from /home/mineq/third_party/boost_1_43_0/boost/spirit/include/qi.hpp:16, from ../InputParser/InputGrammar.h:12, from tests_main.cpp:14: /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/skip_over.hpp: In function ‘void boost::spirit::qi::skip_over(Iterator&, const Iterator&, const T&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, T = boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]::skipper_type]’: In file included from /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/auto/auto.hpp:19, /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:112: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, boost::spirit::qi::skip_flag::enum_type, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0l>]’ /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/parse.hpp:125: instantiated from ‘bool boost::spirit::qi::phrase_parse(Iterator&, Iterator, const Expr&, const Skipper&, Attr&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Expr = InputGrammar<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MockExpressionNode>(), Skipper = MockExpressionNode, Attr = const boost::spirit::ascii::space_type]’ tests_main.cpp:206: instantiated from here /home/mineq/third_party/boost_1_43_0/boost/spirit/home/qi/skip_over.hpp:27: error: ‘const struct MockExpressionNode’ has no member named ‘parse’ make[2]: *** [build/linux_amd64_devel/GNU-Linux-x86/tests_main.o] Error 1 make[2]: se sale del directorio `/home/mineq/NetBeansProjects/InputParserTests' make[1]: *** [.build-conf] Error 2 make[1]: se sale del directorio `/home/mineq/NetBeansProjects/InputParserTests' make: *** [.build-impl] Error 2 BUILD FAILED (exit value 2, total time: 1m 48s)

    Read the article

  • Stateful Iterators Java

    - by Gitmo
    What is a Stateful Iterator? This question relates to an Iterator defined in Hadoop for performing Joins. As the reference documentation states: This defines an interface to a stateful Iterator that can replay elements added to it directly. Note that this does not extend Iterator. What does 'replay elements added to it directly' mean? How is this iterator different from a usual iterator?

    Read the article

  • Isn't an Iterator in c++ a kind of a pointer?

    - by Bilthon
    Ok this time I decided to make a list using the STL. I need to create a dedicated TCP socket for each client. So everytime I've got a connection, I instantiate a socket and add a pointer to it on a list. list<MyTcp*> SocketList; //This is the list of pointers to sockets list<MyTcp*>::iterator it; //An iterator to the list of pointers to TCP sockets. Putting a new pointer to a socket was easy, but now every time the connection ends I should disconnect the socket and delete the pointer so I don't get a huge memory leak, right? well.. I thought I was doing ok by setting this: it=SocketList.begin(); while( it != SocketList.end() ){ if((*it)->getClientId() == id){ pSocket = it; // <-------------- compiler complains at this line SocketList.remove(pSocket); pSocket->Disconnect(); delete pSocket; break; } } But the compiler is saying this: error: invalid cast from type ‘std::_List_iterator<MyTcp*>’ to type ‘MyTcp*’ Can someone help me here? i thought I was doing things right, isn't an iterator at any given time just pointing to one of the elements of the set? how can I fix it?

    Read the article

  • Why do iterators in Python raise an exception?

    - by NullUserException
    Here's the syntax for iterators in Java (somewhat similar syntax in C#): Iterator it = sequence.iterator(); while (it.hasNext()) { System.out.println(it.next()); } Which makes sense. Here's the equivalent syntax in Python: it = iter(sequence) while True: try: value = it.next() except StopIteration: break print(value) I thought Exceptions were supposed to be used only in, well, exceptional circumstances. Why does Python use exceptions to stop iteration?

    Read the article

  • Iterator not accessible because of private inheritance

    - by Bo Tian
    I've created a new class that composes std::deque by private inheritance, i.e, class B : private std::deque<A> { ... }; and in my source code I tried to use iterator of B, i.e., B::iterator it The compiler error is error C2247: 'std::deque<_Ty>::iterator' not accessible because 'B' uses 'private' to inherit from 'std::deque<_Ty>' So the question is, how can I make the iterator accessible?

    Read the article

  • How do I get an Iterator over a vector of objects from a Template?

    - by nieldw
    I'm busy implementing a Graph ADT in C++. I have templates for the Edges and the Vertices. At each Vertex I have a vector containing pointers to the Edges that are incident to it. Now I'm trying to get an iterator over those edges. These are the lines of code: vector<Edge<edgeDecor, vertexDecor, dir>*> edges = this->incidentEdges(); vector<Edge<edgeDecor, vertexDecor, dir>*>::const_iterator i; for (i = edges.begin(); i != edges.end(); ++i) { However, the compiler won't accept the middle line. I'm pretty new to C++. Am I missing something? Why can't I declare an iterator over objects from the Edge template? The compiler isn't giving any useful feedback. Much thanks niel

    Read the article

  • Is there an easy way to copy an iterator into a list in Java?

    - by Space_C0wb0y
    I want something like this: public void CopyIteratorIntoList(Iterator<Foo> fooIterator) { List<Foo> fooList = new ArrayList<Foo>(); fooList.addAll(fooIterator); } which should be equivalent to: public void CopyIteratorIntoList(Iterator<Foo> fooIterator) { List<Foo> fooList = new ArrayList<Foo>(); while(fooIterator.hasNext()) fooList.add(fooIterator.next()); } Is there any method in the API to achieve that, or is this the only way?

    Read the article

  • Obtain container type from (its) iterator type in C++ (STL)

    - by KRao
    It is easy given a container to get the associated iterators, example: std::vector<double>::iterator i; //An iterator to a std::vector<double> I was wondering if it is possible, given an iterator type, to deduce the type of the "corresponding container" (here I am assuming that for each container there is one and only one (non-const) iterator). More precisely, I would like a template metafunction that works with all STL containers (without having to specialize it manually for each single container) such that, for example: ContainerOf< std::vector<double>::iterator >::type evaluates to std::vector<double> Is it possible? If not, why? Thank you in advance for any help!

    Read the article

  • C++: Check istream has non-space, non-tab, non-newline characters left without extracting chars

    - by KRao
    I am reading a std::istream and I need to verify without extracting characters that: 1) The stream is not "empty", i.e. that trying to read a char will not result in an fail state (solved by using peek() member function and checking fail state, then setting back to original state) 2) That among the characters left there is at least one which is not a space, a tab or a newline char. The reason for this is, is that I am reading text files containing say one int per line, and sometimes there may be extra spaces / new-lines at the end of the file and this causes issues when I try get back the data from the file to a vector of int. A peek(int n) would probably do what I need but I am stuck with its implementation. I know I could just read istream like: while (myInt << myIstream) {...} //Will fail when I am at the end but the same check would fail for a number of different conditions (say I have something which is not an int on some line) and being able to differentiate between the two reading errors (unexpected thing, nothing left) would help me to write more robust code, as I could write: while (something_left(myIstream)) { myInt << myIstream; if (myStream.fail()) {...} //Horrible things happened } Thank you!

    Read the article

  • Random begining index iterator for HashSet

    - by funktku
    I use HashSet for add(); remove(); clear(); iterator(); methods. So far everything worked like a charm. However, now I need to fulfill a different requirement. I'd like to be able to start iterating from a certain index. For example, I'd like the following two programs to have same output. Program 1 Iterator it=map.iterator(); for(int i=0;i<100;i++) { it.next(); } while (it.hasNext()) { doSomethingWith(it.next()); } Program 2 Iterator it=map.iterator(100); while (it.hasNext()) { doSomethingWith(it.next()); } The reason I don't want to use the Program 1 is that it creates un-neccesary overhead. From my researchs, I couldn't not find a practical way of creating an iterator with begining index. So, my question is, what would be a good way to achieve my goal while minimizing the overheads? Thank you.

    Read the article

  • Any big difference between using contains or loop through a list?

    - by Nazgulled
    Hi, Performance wise, is there really a big difference between using: ArrayList.contains(o) vs foreach|iterator LinkedList.contains(o) vs foreach|iterator HashMap.(containsKey|containsValue) vs foreach|iterator TreeMap.(containsKey|containsValue) vs foreach|iterator Of course, for the foreach|iterator loops, I'll have to explicitly compare the methods and return true or false accordingly. The object I'm comparing is an object where equals() and hashcode() are both properly overridden.

    Read the article

  • Iterator

    Imagine that you are game developer. Your game is war stategy. Army has complicated structure: it consists with Hero and three Groups. When King gives decree to treat all soldiers (Hero is also soldier) you want to iterate through all soldiers and call treat() method on each soldier instance. How ca

    Read the article

  • Rationale of C# iterators design (comparing to C++)

    - by macias
    I found similar topic: http://stackoverflow.com/questions/56347/iterators-in-c-stl-vs-java-is-there-a-conceptual-difference Which basically deals with Java iterator (which is similar to C#) being unable to going backward. So here I would like to focus on limits -- in C++ iterator does not know its limit, you have by yourself compare the given iterator with the limit. In C# iterator knows more -- you can tell without comparing to any external reference, if the iterator is valid or not. I prefer C++ way, because once having iterator you can set any iterator as a limit. In other words if you would like to get only few elements instead of entire collection, you don't have to alter the iterator (in C++). For me it is more "pure" (clear). But of course MS knew this and C++ while designing C#. So what are the advantages of C# way? Which approach is more powerful (which leads to more elegant functions based on iterators). What do I miss? If you have thoughts on C# vs. C++ iterators design other than their limits (boundaries), please also answer. Note: (just in case) please, keep the discussion strictly technical. No C++/C# flamewar.

    Read the article

  • Trying to use a list iterator to print out entire linked list in Java. Infinite loop for some reaso

    - by Matt
    I created my list: private static List list = new LinkedList(); and my iterator: ListIterator itr = list.listIterator(); and use this code to try to print out the list... Only problem is, it never comes out of the loop. When it reaches the tail, shouldn't it come out of the loop, because there is no next? Or is it going back to the head like a circular linked list? It is printing so quickly and my computer locks up shortly after, so I can't really tell what is going on. while (itr.hasNext()) System.out.println(itr.next());

    Read the article

  • scala implicit or explicit conversion from iterator to iterable

    - by landon9720
    Does Scala provide a built-in class, utility, syntax, or other mechanism for converting (by wrapping) an Iterator with an Iterable? For example, I have an Iterator[Foo] and I need an Iterable[Foo], so currently I am: val foo1: Iterator[Foo] = .... val foo2: Iterable[Foo] = new Iterable[Foo] { def elements = foo1 } This seems ugly and unnecessary. What's a better way?

    Read the article

  • Null pointer exception on .iterator() call

    - by Peter
    I'm getting a strange NullPointerException, evidently thrown by the following line of code: Iterator<Note> it = notes.iterator(); I've checked, and at the time the java.util.TreeSet notes is always non-null (with 15 elements). The TreeSet API says nothing about iterator() throwing NullPointerExceptions. What else could be going here?

    Read the article

  • returning of the iterator in C++

    - by helloWorld
    can somebody explain I can I return list iterator? list<Account>::iterator Company::findAccount(int id){ for(list<Account>::iterator i = listOfAccounts.begin(); i != listOfAccounts.end(); ++i){ if(i->getID() == id){ return i; } } return 0; } and also is it good practice, to return list iterator? edited also can use this function in the statesments: if(findAccount(id)){ throw "hey"; return; }

    Read the article

  • no matching function for call to 'getline'

    - by WTP
    I have a class called parser: class parser { const std::istream& stream; public: parser(const std::istream& stream_) : stream(stream_) {} ~parser() {} void parse(); }; In parser::parse I want to loop over each line, so I use std::getline: std::getline(stream, line) The compiler gives me this error, however: src/parser.cc:10:7: error: no matching function for call to 'getline' std::getline(stream, line); ^~~~~~~~~~~~ But the first argument to std::getline is of type std::istream&, right? What could I be doing wrong?

    Read the article

  • Using boost::iterator_adaptor

    - by Neil G
    I wrote a sparse vector class (see #1, #2.) I would like to provide two kinds of iterators: The first set, the regular iterators, can point any element, whether set or unset. If they are read from, they return either the set value or value_type(), if they are written to, they create the element and return the lvalue reference. Thus, they are: Random Access Traversal Iterator and Readable and Writable Iterator The second set, the sparse iterators, iterate over only the set elements. Since they don't need to lazily create elements that are written to, they are: Random Access Traversal Iterator and Readable and Writable and Lvalue Iterator I also need const versions of both, which are not writable. I can fill in the blanks, but not sure how to use boost::iterator_adaptor to start out. Here's what I have so far: class iterator : public boost::iterator_adaptor< iterator // Derived , value_type* // Base , boost::use_default // Value , boost::?????? // CategoryOrTraversal > class sparse_iterator : public boost::iterator_adaptor< iterator // Derived , value_type* // Base , boost::use_default // Value , boost::random_access_traversal_tag? // CategoryOrTraversal >

    Read the article

  • Call a block method on an iterator: each.magic.collect { ... }

    - by blinry
    I have a class with a custom each-method: class CurseArray < Array def each_safe each.do |element| unless element =~ "fuck" yield element end end end end And want to call block methods on those "selected" elements. For example: curse_array.each_safe.magic.collect {|element| "#{element} is a nice sentence."} I know there is a way to do this, but I've forgotten. Please help! :-)

    Read the article

  • Is it possible to create a python iterator over pre-defined mutable data?

    - by Wilduck
    I might be doing this wrong, if I am, let me know, but I'm curious if the following is possible: I have a class that holds a number of dictionaries, each of which pairs names to a different set of objects of a given class. For example: items = {"ball" : ItemInstance1, "sword" : ItemInstance2} people = {"Jerry" : PersonInstance1, "Bob" : PersonInstance2, "Jill" : PersonInstance3} My class would then hold the current items and people that are availible, and these would be subject to change as the state changes: Class State: def __init__(self, items, people): self.items = items self.people = people I would like to define a iter() and next() method such that it iterates through all of the values in its attributes. My first question is whether or not this is possible. If it is, will it be able to support a situation as follows: I define items and people as above then: state = State(items, people) for names, thing in state: print name + " is " + thing.color items[cheese] = ItemInstance3 for names, thing in state: print name + " weighs " + thing.weight While I feel like this would be usefull in the code I have, I don't know if it's either possible or the right approach. Everything I've read about user defined iterators has suggested that each instance of them is one use only.

    Read the article

  • Design pattern for adding / removing elements

    - by de3
    Wikipedia's definition for Iterator pattern design: the Iterator pattern is a design pattern in which iterators are used to access the elements of an aggregate object sequentially without exposing its underlying implementation. Iterator interface in java provides the following methods hasNext() next() remove() Is there a pattern design, or a java interface for inserting / deleting elements, and getting length of the aggregate object, in addition to iterating them? I know remove() is an optional method that can be used once per call to next(), but I am implementing a circular FIFO array and need a method delete() independent of iterator's next().

    Read the article

  • What to return as an iterator when there is no container?

    - by DaClown
    I have an inheritance structure of objects with begin() and end() as pure virtual member functions in the base class. From this objects I'm planning to build a composite structure. This inner objects have std::vector member the begin() and end() get their data from. But in a leaf class there is no vector. Now I try to find a return value for begin() and end() in the leaf classes. What would be a good way to do that? The easiest way would be to have a vector member in the leaf classes with no elements in it to fuel begin() and end(), but this just doesn't feel right.

    Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >