How do I erase an element from std::vector<> by index?

Question

I have a std::vector<int>, and I want to delete the n'th element. How do I do that?

std::vector<int> vec;  vec.push_back(6); vec.push_back(-17); vec.push_back(12);  vec.erase(???); 

Answer 1

To delete a single element, you could do:

std::vector<int> vec;  vec.push_back(6); vec.push_back(-17); vec.push_back(12);  // Deletes the second element (vec[1]) vec.erase(std::next(vec.begin())); 

Or, to delete more than one element at once:

// Deletes the second through third elements (vec[1], vec[2]) vec.erase(std::next(vec.begin(), 1), std::next(vec.begin(), 3));