C++11 convenience class that mimics the Python enumerate function for range-based for-loops.

Enumerator for C++11

#include <iterator>
#include <type_traits>

// Inspired by:
// http://stackoverflow.com/questions/10962290/find-position-of-element-in-c11-range-based-for-loop
template<typename T>
class Enumerator final {
    public:
        class iterator {
            private:
                typedef typename std::conditional<std::is_const<T>::value, typename T::const_iterator, typename T::iterator>::type inner_iterator;
                typedef typename std::iterator_traits<inner_iterator>::reference inner_reference;
            
            public:
                typedef std::pair<size_t, inner_reference> reference;
                
                iterator(inner_iterator it) : _pos(0), _it(it) {}
                
                reference operator*() const {
                    return reference(_pos, *_it);
                }
                
                iterator& operator++() {
                    ++_pos;
                    ++_it;
                    return *this;
                }
                
                iterator operator++(int) {
                    iterator tmp(*this);
                    operator++();
                    return tmp;
                }
                
                bool operator== (const iterator& it) const {
                    return _it == it._it;
                }
                
                bool operator!= (const iterator& it) const {
                    return _it != it._it;
                }
            
            private:
                size_t _pos;
                inner_iterator _it;
        };
        
        Enumerator(T& t) : _container(t) {}
        
        iterator begin() const { return iterator(_container.begin()); }
        iterator end() const { return iterator(_container.end()); }
    
    private:
        T& _container;
};

// Example usage:
int main(int argc, char** argv) {
    std::string test = "Can_I_be_enumerated?";
    
    for (auto p : enumerate(test))
        // p.first is the index, p.second the current value
        std::cout << p.first << ", " << p.second << std::endl;

    return 0;
}