I'm trying to implement an iterator which encapsulates another iterator and performs range checking. Therefore I'm extending from that Iterator like so:
template<typename ITERATOR_T>
class r_iterator : public ITERATOR_T {
//...
r_iterator (ITERATOR_T begin, ITERATOR_T end) {
this->begin = begin;
this->end = end;
}
};
I want to use the iterators that are passed in the constructor to perform the range checking. My idea is to set the thing to which the "this"-iterator (i.e. r_iterator) points to to the element which is pointed to by the "begin" iterator from the constructor. This I would like to do so I can override certain methods like operator++ for example, perform range checking and then call the super method of the class I'm extending.
I would thus like to know whether it is possible to somehow set the element the "this"-iterator (r_iterator) points to assuming that I'm extending some STL Iterator class.
I could unfortunately not find any information about that in the c++ reference.
Regards and Thank you
There's no need to inherit, you can write a simple wrapper class like this:
#include <iostream>
#include <vector>
#include <stdexcept>
template <typename Iterator>
class MyIterator
{
Iterator _begin;
Iterator _end;
Iterator _cur;
public:
explicit MyIterator(Iterator begin, Iterator end)
: _begin(begin), _end(end)
{
_cur = _begin;
}
bool has_next() const
{
return (_cur != _end);
}
void operator++(int dummy)
{
if (!has_next())
throw std::out_of_range("Out of range.");
_cur++;
}
};
int main(int argc, char* argv[])
{
std::vector<int> v = {1, 2, 3};
MyIterator<std::vector<int>::iterator> my_it(v.begin(), v.end());
my_it++;
my_it++;
my_it++;
my_it++;
return 0;
}