stdvector

Finally I'm able to use std::vector in python using the [] operator. The trick is to simple provide a container in the boost C++ wrapper which handles the internal vector stuff: #include <boost/python.hpp> #include <vector> class world { std::vector<double> myvec; void add(double n) { this->myvec.push_back(n); } std::vector<double> show() { return this->myvec; } }; BOOST_PYTHON_MODULE(hello) { class_<std::vector<double> >("double_vector") .def(vector_indexing_suite<std::vector<double> >()) ; class_<World>("World") .def("show", &World::show) .def("add", &World::add) ; } The other challenge is:

I have the following Java code with several big arrays which never change their size. It runs in 1100 ms on my computer. I implemented the same code in C++ and used std::vector . The time of the C++ implementation which runs the exact same code is 8800 ms on my computer. What did I do wrong, so that it runs this slowly? Basically the code does the following: for (int i = 0; i < numberOfCells; ++i) { h[i] = h[i] + 1; floodedCells[i] = !floodedCells[i]; floodedCellsTimeInterval[i] = !floodedCellsTimeInterval[i]; qInflow[i] = qInflow[i] + 1; } It iterates through different arrays with a size of

I am still confused about the requirements for a type to be used with a std::vector in C++11, but this may be caused by a buggy compiler (gcc 4.7.0). This code: struct A { A() : X(0) { std::cerr<<" A::A(); this="<<this<<'\n'; } int X; }; int main() { std::vector<A> a; a.resize(4); } works fine and produces the expected output, indicating that the default ctor (explicitly given) is called (and not an implicit copy ctor). However, if I add a deleted copy ctor to the class, viz struct A { A() : X(0) { std::cerr<<" A::A(); this="<<this<<'\n'; } A(A const&) = delete; int X; }; gcc 4.7.0 does not

Pretty self explanatory. Here's the method that's causing the SIGABRT on the 'new vector' line: vector<string> * Task::arguments() { vector<string> *args = new vector<string>(); // CAUSES SIGABRT int count = sizeof(_arguments); for (int x = 0; x < count; x++) { string argument(_arguments[x]); args->push_back(argument); } return args; } Note that elsewhere I call that exact line without any issues. Here is the list of includes in the Task class: #include <vector> #include <unistd.h> #include <string> using namespace std; #include <sys/types.h> #include <sys/wait.h> #include <signal.h> Any

the following code doesn't compile with gcc 4.7.0 (using std=c++11 -O3) int n; std::vector< int[4] > A; A.resize(n); the error message is length, but eventually functional cast to array type ‘_ValueType {aka int[4]}‘ Is this correct? or should this compile? And more importantly, how to avoid this problem? (without defining a new struct to hold the int[4] ) EDIT: how to solve the problem with C++98? heretolearn You cannot store arrays in a vector or any other container. The type of the elements to be stored in a container (called the container's value type) must be both copy constructible and

Consider this example: #include <iostream> #include <string> #include <vector> #include <iterator> int main() { std::string sen = "abc def ghi jkl"; std::istringstream iss(sen); std::vector<std::string> // declaration in question vec(std::istream_iterator<std::string>(iss), std::istream_iterator<std::string>()); std::copy(vec.begin(), vec.end(), std::ostream_iterator<std::string>(std::cout, "\n")); } The compiler throws an error at the call to std::copy request for member 'begin' in 'vec', which is of non-class type... I can get around the error like this: std::istream_iterator<std::string> it