vector.pop_back() Question

I am trying to remove an element from a vector, and I was told to use vector.pop_back(), but from the tutorial on this site, it claims the member function removes the last element. So if my vector.size() = 30, i.e., and I wanted to remove vector[12], how would my code look using .pop_back()?!? Thanks for the help!!

If the pop_back function removes the last element, then it wouldn't make sense to try and use it to remove an element that is somewhere in the middle. Use the erase member function instead.

erase [C++ Reference]