auto x1 = exp1;
auto& x2 = exp2;
Do I understand correctly that variables declared with auto (x1) will never be const, even if exp1 is const (for ex. a function that returns const). When with auto&(x2) will be const if exp2 will be const. Even if auto is a pointer.
auto it = find(cont.cbegin(), cont.cend(), value);
Here despite I use cbegin and cend it will be non-const iterator, and to be const_iterator I should write
const auto it1 = find(cont.cbegin(), cont.cend(), value);
Do I understand correctly that variables declared with auto (x1) will never be const
Correct.
When with auto&(x2) will be const if exp2 will be const.
A reference is never const; references cannot be cv qualified. x2 could be a reference to const.
auto it = find(cont.cbegin(), cont.cend(), value);Here despite I use cbegin and cend it will be non-const iterator
it would be a non-const qualified object of const_iterator type.
const auto it1 = find(cont.cbegin(), cont.cend(), value);
it1 would be a const qualified object of const_iterator type.
Indirecting through a const_iterator (typically) gives you a reference to const, and thus you cannot modify the pointed object.
A const object cannot (generally) be modified. Thus, you for example cannot increment a const qualified iterator.