Question

Which is the following is syntactically correct for vector<int> v?

(a) vector <int> :: const_iterator itr = v.rbegin();

(b) vector <int> :: reverse_iterator itr = v.begin();

(c) vector <int> :: iterator itr = v.begin();

(d) vector <int> :: iterator itr = v.cbegin();

I have been asked this question in class test.

This interesting question is from seq_con Vector Class in chapter Class Hierarchies, Library & Containers of C++

Answer 1

Correct option is (c) vector <int> :: iterator itr = v.begin();

To explain I would say: v.rbegin() returns itertor of reverse iterator therefore cannot be stored in const_iterator(type mismatch). Similarly v.begin() returns normal iterator therefore cannot be stored in reverse_iterator and v.cbegin() returns the const_iterator therefore cannot be stored in normal iterator.