#include <cstdlib>
#include <vector>
using namespace std;

int main()
{
	int a[] = {10, 20, 30};
	size_t n = sizeof a / sizeof a[0];
	vector<int> v(a, a + n);

	const vector<int>::iterator it1 = v.begin();
	//++it1;     //won't compile: it1 must always refer to v[0]

	vector<int>::const_iterator it2 = v.begin();
	//++*it2;    //won't compile: can't use it2 to change v[0] from 10 to 11

	const vector<int>::const_iterator it3 = v.begin();   //both of the above
	//++it3;     //won't compile: it3 must always refer to v[0]
	//++*it3;    //won't compile: can't use it3 to change v[0] from 10 to 11

	v[0] = 11;   //v.operator[](0) = 11
	return EXIT_SUCCESS;
}