vector

问题 I am attempting to write a program which can read in a text file, and store each word in it as an entry in a string type vector. I am sure that I am doing this very wrong, but it has been so long since I have tried to do this that I have forgotten how it is done. Any help is greatly appreciated. Thanks in advance. Code: #include <iostream> #include <fstream> #include <vector> #include <string> using namespace std; int main() { vector<string> input; ifstream readFile; vector<string>::iterator

问题 I'm looking into a way of efficiently creating a derangement (and conversely specific permutations) of a vector in R. As far as I've seen, there's no base function that does that and also there's not much about it here on SO. An obvious start is sample which creates a permutation of a vector. But I need this permutation to have no fixed points, hence be a derangement of the vector. For a nice explanation of this topic, see this Cross Validated post. This is my first approach: derangr <-

问题 I'm trying to debug a program, and in doing so have bumped up against my understanding of the C++ vector push_back() function. To illustrate my point, I've written the following short program: #include <iostream> #include <vector> #include <cstdlib> using std::cout; using std::endl; using std::vector; class Test { private: int mTestMember; public: Test(int val); Test(const Test&); int GetValue() const; }; Test::Test(int val) { cout << "Constructor\n"; mTestMember = val; } Test::Test(const

问题 This question already has answers here : How do I print out the contents of a vector? (30 answers) Closed 5 years ago . I need to cout a vector. Not just an element of it, but the whole thing. For example std::cout << vectorName; Something like that, hope it makes sense. Any ideas? Thanks in advance 回答1: You can either define a utility function like template <typename T> ostream& operator<<(ostream& output, std::vector<T> const& values) { for (auto const& value : values) { output << value <<

问题 Please consider the following code. I'm trying to output a vector of vectors to an ostream. #include <iterator> #include <iostream> #include <string> #include <vector> #include <algorithm> template<typename T> std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) { using namespace std; copy(v.begin(), v.end(), ostream_iterator<T>(os, "\n")); return os; } int main() { using namespace std; vector<string> v1; cout << v1; vector<vector<string> > v2; cout << v2; return 0; } The

问题 Please consider the following code. I'm trying to output a vector of vectors to an ostream. #include <iterator> #include <iostream> #include <string> #include <vector> #include <algorithm> template<typename T> std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) { using namespace std; copy(v.begin(), v.end(), ostream_iterator<T>(os, "\n")); return os; } int main() { using namespace std; vector<string> v1; cout << v1; vector<vector<string> > v2; cout << v2; return 0; } The

问题 Please consider the following code. I'm trying to output a vector of vectors to an ostream. #include <iterator> #include <iostream> #include <string> #include <vector> #include <algorithm> template<typename T> std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) { using namespace std; copy(v.begin(), v.end(), ostream_iterator<T>(os, "\n")); return os; } int main() { using namespace std; vector<string> v1; cout << v1; vector<vector<string> > v2; cout << v2; return 0; } The

问题 Please consider the following code. I'm trying to output a vector of vectors to an ostream. #include <iterator> #include <iostream> #include <string> #include <vector> #include <algorithm> template<typename T> std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) { using namespace std; copy(v.begin(), v.end(), ostream_iterator<T>(os, "\n")); return os; } int main() { using namespace std; vector<string> v1; cout << v1; vector<vector<string> > v2; cout << v2; return 0; } The

问题 I've checked a lot of move constructor/vector/noexcept threads, but I am still unsure what actually happens when things are supposed to go wrong. I can't produce an error when I expect to, so either my little test is wrong, or my understanding of the problem is wrong. I am using a vector of a BufferTrio object, which defines a noexcept(false) move constructor, and deletes every other constructor/assignment operator so that there's nothing to fall back to: BufferTrio(const BufferTrio&) =

问题 I've checked a lot of move constructor/vector/noexcept threads, but I am still unsure what actually happens when things are supposed to go wrong. I can't produce an error when I expect to, so either my little test is wrong, or my understanding of the problem is wrong. I am using a vector of a BufferTrio object, which defines a noexcept(false) move constructor, and deletes every other constructor/assignment operator so that there's nothing to fall back to: BufferTrio(const BufferTrio&) =