/////////////////////////////////////////////////////////////////////
// MT3Q2.cpp

#include <list>
#include <iostream>
#include <iomanip>
#include <math.h>
#include <time.h>

template <typename T>
class RunningInterval
{
public:
  RunningInterval(size_t n) : interval(n) {}
  void addDataPoint(const T& t);
  T avg() const;
  T front() const { return runningList.front(); }
  T back() const { return runningList.back(); }
  size_t size() const { return runningList.size(); }
private:
  size_t interval;
  std::list<T> runningList;
};

template <typename T>
void RunningInterval<T>::addDataPoint(const T& t)
{
  runningList.push_back(t);
  if(runningList.size() > interval)
    runningList.pop_front();
}

template <typename T>
T RunningInterval<T>::avg() const
{ 
  T avg_ = T(0);
  std::list<T>::const_iterator iter;
  for(iter=runningList.begin(); iter!=runningList.end(); ++iter)
  {
    avg_ += *iter;
  }
  return avg_/static_cast<T>(size());
}

void main()
{
  RunningInterval<int> runningInts(8);
  srand( (unsigned)time(0) );
  for(int i=0; i<25; ++i)
  {
    int data = rand();
    runningInts.addDataPoint(data);
    std::cout << "\n  list length = " << std::setw(2) << runningInts.size();
    std::cout << ", data = " << std::setw(5) << data;
    std::cout << ", avg = "  << std::setw(5) << runningInts.avg();
  }
  std::cout << "\n  front is " << runningInts.front();
  std::cout << "\n  back is  " << runningInts.back();
  std::cout << "\n\n";
}