std::vector<int> vec;
...
const std::vector<int>::iterator iter = vec.begin(); //iter 는 T* const 처럼 동작
*iter = 10; //동작
++iter; //에러
std::vector<int>::const_iterator cIter = vec.begin(); //cIter는 const T* 처럼 동작
*cIter = 10;//에러
++cIter;//동작