// Oldham, Jeffrey D.
// 2000 Mar 20
// CS3352

// Histogram That Buckets Data

// This program read in data and the desired number of buckets,
// determines the minimum and maximum range of values, and then
// prints, for each bucket, a typical bucket entry and the number of
// items in each bucket.

// Implementation

// Data is stored in a map, which is a class in the Standard Template
// Library (http://www.sgi.com/Technology/STL/).  Conceptually, a map
// is a collection of pairs (key, value), sorted according to keys.

// We use a map<inputType,unsigned long> map, i.e., it contains pairs
// of objects with type "inputType" and "unsigned long".  "inputType"
// represents the type of the input data, e.g., int, string, double.
// "unsigned long" represents the number of occurrences of a particular 
// item.

// We assume inputType is numeric so we can compute bucket sizes.

typedef int inputType;		// type of input data
				// Change this if necessary.

#include <map>
#include <iostream.h>
#include <stdlib.h>		// has EXIT_SUCCESS
#include <errno.h>		// has errno


template <typename T, T Teps = 1> // bucket type and smallest difference
class bucket {
public:
  bucket(const T bucketBegin, const T width, const unsigned long total) :
    bucketWidth(width), bucketEd(bucketBegin+bucketWidth),
    totalNuItems(total), count(0) {}
  void incrementEnd(void) { bucketEd += bucketWidth; count = 0; return; }
  T bucketEnd(void) const { return bucketEd; }
  bucket& operator+=(const unsigned long cnt) { count += cnt; return *this; }

  friend ostream& operator<<(ostream& out, const bucket & b) {
    return out << static_cast<T>(b.bucketEd-Teps - b.bucketWidth/2) << '\t' <<
      b.count / static_cast<double>(b.totalNuItems*b.bucketWidth) << endl;
  }
private:
  const T bucketWidth;
  T bucketEd;
  const unsigned long totalNuItems;
  unsigned long count;
};

int main(int argc, char *argv[])
{
  // Determine the number of buckets.
  unsigned long nuBuckets = 0;
  if (argc > 2) {
    cerr << argv[0] << ": [number-of-buckets]\n";
    return EXIT_FAILURE;
  }
  else if (argc == 2) {
    errno = 0;
    char *tail;
    nuBuckets = strtoul(argv[1], &tail, 0);
    if (errno || *tail != '\0') {
      cerr << argv[0] << ": [number-of-buckets]\n";
      return EXIT_FAILURE;
    }
  }

  // Read the data.
  unsigned long count = 0;
  map<inputType, unsigned long> histogramMap;
  inputType i;
  while (cin >> i) {
    ++histogramMap[i];		// increase element i's count
    ++count;
  }

  // Print the results.
  map<inputType, unsigned long>::const_iterator ender = histogramMap.end();
  --ender;

  map<inputType, unsigned long>::const_iterator pos;
  bucket<inputType,1> b((*histogramMap.begin()).first,
			nuBuckets == 0 ? 1 : 
			(ender->first - (*histogramMap.begin()).first + 1 /* Teps */)
			/ static_cast<double>(nuBuckets),
			count);
  for (pos = histogramMap.begin(); pos != histogramMap.end(); ++pos)
    if (pos->first >= b.bucketEnd()) {
      cout << b;
      b.incrementEnd();
      b += pos->second;
    }
    else
      b += pos->second;
  cout << b;
      
  return EXIT_SUCCESS;
}