stdvector

That is the point. How to write and read binary files with std::vector inside them? I was thinking something like: //============ WRITING A VECTOR INTO A FILE ================ const int DIM = 6; int array[DIM] = {1,2,3,4,5,6}; std::vector<int> myVector(array, array + DIM); ofstream FILE(Path, ios::out | ofstream::binary); FILE.write(reinterpret_cast<const char *>(&myVector), sizeof(vector) * 6); //=========================================================== But I don't know how to read this vector. Because I thought that the following was correctly but it isn't: ifstream FILE(Path, ios::in |

I know that at() is slower than [] because of its boundary checking, which is also discussed in similar questions like C++ Vector at/[] operator speed or ::std::vector::at() vs operator[] << surprising results!! 5 to 10 times slower/faster! . I just don't understand what the at() method is good for. If I have a simple vector like this one: std::vector<int> v(10); and I decide to access its elements by using at() instead of [] in situation when I have a index i and I'm not sure if its in vectors bounds, it forces me to wrap it with try-catch block : try { v.at(i) = 2; } catch (std::out_of_range

I have declared the following in my code vector <const A> mylist; I get the following compile error - new_allocator.h:75: error: `const _Tp* __gnu_cxx::new_allocator<_Tp>::address(const _Tp&) const \[with _Tp = const A]' and `_Tp* __gnu_cxx::new_allocator<_Tp>::address(_Tp&) const [with _Tp = const A]' cannot be overloaded But if declare - vector <A> mylist; my code compiles. Is const not allowed in this context? I am copying my code here for everyone'e reference - #include <iostream> #include <vector> using namespace std; class A { public: A () {cout << "default constructor\n";} A (int i): m

When I use clear() on a std::vector , it is supposed to destroy all the elements in the vector , but instead it doesn't. Sample code: vector<double> temp1(4); cout << temp1.size() << std::endl; temp1.clear(); cout << temp1.size() << std::endl; temp1[2] = 343.5; // I should get segmentation fault here .... cout << "Printing..... " << temp1[2] << endl; cout << temp1.size() << std::endl; Now, I should have gotten segmentation fault while trying to access the cleared vector, but instead it fills in the value there (which according to me is very buggy) Result looks as follows: 4 0 Printing..... 343

In the following code: std::vector<int> var; for (int i = 0; i < var.size(); i++); Is the size() member function called for each loop iteration, or only once? In theory , it is called each time, since a for loop: for(initialization; condition; increment) body; is expanded to something like { initialization; while(condition) { body; increment; } } (notice the curly braces, because initialization is already in an inner scope) In practice , if the compiler understands that a piece of your condition is invariant through all the duration of the loop and it does not have side-effects , it can be

I have an object that I want to travel in a continuous loop in a game. I have a series of coordinates in a std::vector that I want to use as waypoints. Is there any way to make an std::vector<T>::iterator cyclic (also known as a circulator)? The best I can come up with is to have two iterators and then whenever the first iterator is exhausted assign to it the value of the second (which would not be used to do anything else) but I am not even sure it will work - will the assignment operator copy whatever the iterator is using to hold the index or will it merely be referenced (and therefore will