Is it legal to add elements to a preallocated vector in a range-based for loop over that vector?

Question

I\'m using Visual Studio 2015 Update 1 C++ compiler and this code snippet:

#include 
#include 

using namespace std;

int main(         


        

Answer 1

According to documentation:

If the new size() is greater than capacity() then all iterators and references (including the past-the-end iterator) are invalidated. Otherwise only the past-the-end iterator is invalidated.

It says even if capacity is enough past-the-end iterator is invalidated, so I believe your code has UB (unless this documentation is incorrect and standard says otherwise)