//: C10:FibonacciAdapter.cpp
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// Adapting an interface to something you already have.
#include <iostream>
#include <numeric>
#include "FibonacciGenerator.h"
#include "../C06/PrintSequence.h"
using namespace std;

class FibonacciAdapter { // Produce an iterator
  FibonacciGenerator f;
  int length;
public:
  FibonacciAdapter(int size) : length(size) {}
  class iterator;
  friend class iterator;
  class iterator : public std::iterator<
    std::input_iterator_tag, FibonacciAdapter, ptrdiff_t> {
    FibonacciAdapter& ap;
  public:
    typedef int value_type;
    iterator(FibonacciAdapter& a) : ap(a) {}
    bool operator==(const iterator&) const {
      return ap.f.count() == ap.length;
    }
    bool operator!=(const iterator& x) const {
      return !(*this == x);
    }
    int operator*() const { return ap.f(); }
    iterator& operator++() { return *this; }
    iterator operator++(int) { return *this; }
  };
  iterator begin() { return iterator(*this); }
  iterator end() { return iterator(*this); }
};

int main() {
  const int SZ = 20;
  FibonacciAdapter a1(SZ);
  cout << "accumulate: "
    << accumulate(a1.begin(), a1.end(), 0) << endl;
  FibonacciAdapter a2(SZ), a3(SZ);
  cout << "inner product: "
    << inner_product(a2.begin(), a2.end(), a3.begin(), 0)
    << endl;
  FibonacciAdapter a4(SZ);
  int r1[SZ] = {0};
  int* end = partial_sum(a4.begin(), a4.end(), r1);
  print(r1, end, "partial_sum", " ");
  FibonacciAdapter a5(SZ);
  int r2[SZ] = {0};
  end = adjacent_difference(a5.begin(), a5.end(), r2);
  print(r2, end, "adjacent_difference", " ");
} ///:~