stdvector

Consider the following program which inserts a range of elements into a vector: vector<string> v1; vector<string> v2; v1.push_back("one"); v1.push_back("two"); v1.push_back("three"); v2.push_back("four"); v2.push_back("five"); v2.push_back("six"); v1.insert(v1.end(), v2.begin(), v2.end()); This efficiently copies the range, allocating enough space in the target vector for the entire range so that a maximum of one resize will be required. Now consider the following program which attempts to move a range into a vector: vector<string> v1; vector<string> v2; v1.push_back("one"); v1.push_back("two"

I would like to be able to convert between std::vector and its underlying C array int* without explicitly copying the data. Does std::vector provide access to the underlying C array? I am looking for something like this vector<int> v (4,100) int* pv = v.c_array(); EDIT: Also, is it possible to do the converse, i.e. how would I initialize an std::vector from a C array without copying? int pv[4] = { 4, 4, 4, 4}; vector<int> v (pv); You can get a pointer to the first element as follows: int* pv = &v[0]; This pointer is only valid as long as the vector is not reallocated. Reallocation happens

I'm currently trying to make a Wavefront (.obj) file loader for an OpenGL project. The method I'm currently using goes line-by-line and separates the vertex positions, texture positions and normal positions in vectors (std::vectors) and I'm storing their indices (vertex, texture and normal indices) in three separate vectors (from the 'f' lines of the file, for each face). I'm having trouble sorting the vector full of texture coordinates based on the texture indices. I'm able to render the vertices in the correct positions because my 'loader' class calls for the indices, but I can't figure out

I have tried this code in a totally separate project, and it works fine (the only difference being that the project that is not working is being exported as a DLL). Here is the code: RTATMATHLIB.CPP #include "stdafx.h" #include "RTATMATHLIB.h" #include <math.h> #include <vector> #include <algorithm> #include <stdexcept> using namespace std; double someFunc(double** Y, int length) { vector<double> myVector; for(int i = 0; i < length; i++) { double value = (*Y)[i]; vector<double>::iterator it = find(myVector.begin(), myVector.end(), value); if(it != myVector.end()) { continue; } else { myVector

Possible Duplicate: How to enforce move semantics when a vector grows? insert , push_back and emplace ( _back ) can cause a reallocation of a std::vector . I was baffled to see that the following code copies the elements instead of moving them while reallocating the container. #include <iostream> #include <vector> struct foo { int value; explicit foo(int value) : value(value) { std::cout << "foo(" << value << ")\n"; } foo(foo const& other) noexcept : value(other.value) { std::cout << "foo(foo(" << value << "))\n"; } foo(foo&& other) noexcept : value(std::move(other.value)) { other.value = -1;

The C++ standard seems to make no statement regarding side-effects on capacity by either resize(n) , with n < size() , or clear() . It does make a statement about amortized cost of push_back and pop_back - O(1) I can envision an implementation that does the usual sort of capacity changes ala CLRS Algorithms (e.g. double when enlarging, halve when decreasing size to < capacity()/4 ). (Cormen Lieserson Rivest Stein) Does anyone have a reference for any implementation restrictions? mattnewport Calling resize() with a smaller size has no effect on the capacity of a vector . It will not free memory