/////////////////////////////////////////////////////////////////////
// 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";
}

  list length =  1, data = 12684, diff =     0
  list length =  2, data = 29315, diff = 16631
  list length =  3, data = 13542, diff = 16631
  list length =  4, data = 15509, diff = 16631
  list length =  5, data = 23791, diff = 16631
  list length =  6, data = 10716, diff = 18599
  list length =  7, data = 31894, diff = 21178
  list length =  8, data = 19859, diff = 21178
  list length =  8, data = 24075, diff = 21178
  list length =  8, data = 17799, diff = 21178
  list length =  8, data =  6875, diff = 25019
  list length =  8, data = 13367, diff = 25019
  list length =  8, data =  9735, diff = 25019
  list length =  8, data = 14623, diff = 25019
  list length =  8, data =  8112, diff = 17200
  list length =  8, data = 16417, diff = 17200
  list length =  8, data =  1874, diff = 15925
  list length =  8, data =  2405, diff = 14543
  list length =  8, data = 18595, diff = 16721
  list length =  8, data =  5430, diff = 16721
  list length =  8, data = 16522, diff = 16721
  list length =  8, data = 15251, diff = 16721
  list length =  8, data =   728, diff = 17867
  list length =  8, data = 13721, diff = 17867
  list length =  8, data = 11933, diff = 17867
  front is 2405
  back is  11933