const pointer in for loop (C++ 11)

Can someone explain me why it is possible to declare a const pointer to something that has a different value for each iteration of the loop?

#include <assimp/Importer.hpp>
...

for (int i = 0; i < N; i++) {
    const aiVector3D* vp = &(mesh->mVertices[i]);
    // use vp.x ...
}

This snippet is part of an example code of how to use assimp to import mesh-data. (i am new to c++)