#include <cassert>

int main() {
    int values[]{2, 4, 6};
    int* first = values;
    int* last = values + 3;
    int sum = 0;
    for (int* p = first; p != last; ++p) {
        sum += *p;
    }
    assert(sum == 12);
    assert(last - first == 3);
    int* optional = nullptr;
    assert(optional == nullptr);
    optional = &values[1];
    *optional = 9;
    assert(values[1] == 9);
}