如何删除const_iterator的constness？

#include<iostream>
#include<vector>

int main() {
    std::vector<int> vec = {1, 2, 3, 4, 5};

    std::vector<int>::const_iterator const_iter = vec.begin();
    std::vector<int>::iterator iter = const_cast<std::vector<int>::iterator>(const_iter);

    iter++;
    *iter = 42;

    std::cout << "Modified value: " << *iter<< std::endl;

    return 0;
}