subgraph.hpp

/**
 * @file subgraph.hpp
 * Implimentation file for viewing a subgraph from our Graph
 */


#include <fstream>
#include <iterator>

#include "CME212/SFML_Viewer.hpp"
#include "CME212/Util.hpp"

#include "Graph.hpp"

/** An iterator that skips over elements of another iterator based on whether
 * those elements satisfy a predicate.
 *
 * Given an iterator range [@a first, @a last) and a predicate @a pred,
 * this iterator models a filtered range such that all i with
 * @a first <= i < @a last and @a pred(*i) appear in order of the original range.
 */
template <typename Pred, typename It>
class filter_iterator : private equality_comparable<filter_iterator<Pred,It>>
{
 public:
  // Get all of the iterator traits and make them our own
  using value_type        = typename std::iterator_traits<It>::value_type;
  using pointer           = typename std::iterator_traits<It>::pointer;
  using reference         = typename std::iterator_traits<It>::reference;
  using difference_type   = typename std::iterator_traits<It>::difference_type;
  using iterator_category = typename std::input_iterator_tag;

  // Constructor
  filter_iterator(const Pred& p, const It& first, const It& last)
      : p_(p), it_(first), end_(last) {
    // HW1 #4: YOUR CODE HERE
  }

  // HW1 #4: YOUR CODE HERE
  // Supply definitions AND SPECIFICATIONS for:
  // value_type operator*() const;
  // filter_iterator& operator++();
  // bool operator==(const self_type&) const;

 private:
  Pred p_;
  It it_;
  It end_;
};

/** Helper function for constructing filter_iterators. This deduces the type of
 * the predicate function and the iterator so the user doesn't have to write it.
 * This also allows the use of lambda functions as predicates.
 *
 * Usage:
 * // Construct an iterator that filters odd values out and keeps even values.
 * std::vector<int> a = ...;
 * auto it = make_filtered(a.begin(), a.end(), [](int k) {return k % 2 == 0;});
 */
template <typename Pred, typename Iter>
filter_iterator<Pred,Iter> make_filtered(const Iter& it, const Iter& end,
                                         const Pred& p) {
  return filter_iterator<Pred,Iter>(p, it, end);
}

// HW1 #4: YOUR CODE HERE
// Specify and write an interesting predicate on the nodes.
// Explain what your predicate is intended to do and test it.
// If you'd like you may create new nodes and tets files.

/** Test predicate for HW1 #4 */
struct SlicePredicate {
  template <typename NODE>
  bool operator()(const NODE& n) {
    return n.position().x < 0;
  }
};