Re: Deriving an iterator

From:
jononanon@googlemail.com
Newsgroups:
comp.lang.c++
Date:
Sat, 27 Dec 2014 10:17:53 -0800 (PST)
Message-ID:
<392547a6-e783-4b69-bcb4-422632898737@googlegroups.com>
OK, here's how to SOLVE it:

Instead of
static_cast<vector<T>>(*this).begin()
USE THIS:
static_cast<vector<T>*>(this)->begin()

But the more important question: why does only the 2nd one work correctly???

Thanks for any help and pointers ;) on this!!

J.

Below is the full code:
///////////////////////////////////////////////////////

#include <iostream>
#include <vector>

using std::vector;

template<typename T>
struct Myvec : public vector<T> {
  using vector<T>::vector;

  class myiterator;

  myiterator begin1() {return myiterator{static_cast<vector<T>*>(this)->begin()}; }
  myiterator end1() {return myiterator{static_cast<vector<T>*>(this)->end()}; }
  const myiterator begin1()const {return myiterator{static_cast<vector<T>*>(this)->begin()}; }
  const myiterator end1() const {return myiterator{static_cast<vector<T>*>(this)->end()}; }

};

template<typename T>
struct Myvec<T>::myiterator : public vector<T>::iterator{
  // CONSTRUCTOR
  myiterator(const typename vector<T>::iterator& it) : vector<T>::iterator{it} {}
  using vector<T>::iterator::iterator;
};

int main()
{
  Myvec<int> vec = {1, 2, 3};
  for (Myvec<int>::myiterator it = vec.begin1(); it != vec.end1(); ++it) {
    std::cout << *it << '\n';
  }

  return 0;
}

///////////////////////////////////////////////////////

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