Can I use const in vectors to allow adding elements, but not modifications to the already added?

Question

My comments on this answer got me thinking about the issues of constness and sorting. I played around a bit and reduced my issues to the fact that this code:

Answer 1

Using just an unspecialized vector, this can't be done. Sorting is done by using assignment. So the same code that makes this possible:

sort(v.begin(), v.end());

...also makes this possible:

v[1] = 123;