Custom Iterator in C++

Question

I have a class TContainer that is an aggregate of several stl collections pointers to TItems class.

I need to create an Iterator to traverse the elements in all the

Answer 1

This is the simplest code I was able to produce (for custom iterators). Note that I'm only beginning to explore this area. This calls built-in upper_bound function to perform binary search on an integer function, x^2 as an example.

#include 
#include 

using namespace std;

class Iter
{
  public:
  int x;
  Iter() { x = -1; }
  Iter(int a) { x = a; }

  bool operator!=(Iter &i2) const { return x != i2.x; }
  void operator++() { x++; }
  void operator+=(int b) { x += b; }
  int operator-(const Iter &i2) const { return x - i2.x; }
  int operator*() const {
    cout << "calculating for x " << x << endl;
    return x*x;
  }

  typedef random_access_iterator_tag iterator_category;
  typedef int value_type;
  typedef int difference_type;
  typedef int* pointer;
  typedef int& reference;
};

main ()
{
  ios::sync_with_stdio(false);
  cout << upper_bound(Iter(0), Iter(100), 40).x << endl;
}

// :collapseFolds=1:folding=explicit:

And this is how the output looks like:

calculating for x 50
calculating for x 25
calculating for x 12
calculating for x 6
calculating for x 9
calculating for x 8
calculating for x 7
7