/////////////////////////////////////////////////////////////////////
// MT1Q2.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 span();
  T front() { return runningList.front(); }
  T back() { return runningList.back(); }
  size_t size() { return runningList.size(); }
private:
  size_t interval;
  std::list<T> runningList;
  int max_;
  int min_;
};

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>::span()
{ 
  max_ = -RAND_MAX;
  min_ = RAND_MAX;
  std::list<T>::iterator iter;
  for(iter=runningList.begin(); iter!=runningList.end(); ++iter)
  {
    if(max_ < *iter) max_ = *iter;
    if(min_ > *iter) min_ = *iter;
  }
  return max_ - min_; 
}

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 << ", diff = "  << std::setw(5) << runningInts.span();
  }
  std::cout << "\n  front is " << runningInts.front();
  std::cout << "\n  back is  " << runningInts.back();
  std::cout << "\n\n";
}