Returns a const iterator that points to the first element in the range.
cbegin is used for read-only access with const_iterators.
You can use this member function in place of the begin() member function to guarantee that the return value is const_iterator. Typically, it's used in conjunction with the auto type deduction keyword, as shown in the following example. In the example, consider Container to be a modifiable (non-const) container of any kind that supports begin() and cbegin().