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  24 
  25 // This class implements a simple histogram.
  26 
  27 // A histogram summarizes a series of "measurements", each of which is
  28 // assumed (required in this implementation) to have an outcome that is a
  29 // non-negative integer.  The histogram efficiently maps measurement outcomes
  30 // to the number of measurements had that outcome.
  31 
  32 // To print the results, invoke print() on your Histogram*.
  33 
  34 // Note: there is already an existing "Histogram" class, in file
  35 // histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table
  36 // mapping strings to counts.  To be a histogram (IMHO) it needs to map
  37 // numbers (in fact, integers) to number of occurrences of that number.
  38 
  39 // ysr: (i am not sure i agree with the above note.) i suspect we want to have a
  40 // histogram template that will map an arbitrary type (with a defined order
  41 // relation) to a count.
  42 
  43 
  44 class IntHistogram : public CHeapObj {
  45  protected:
  46   int _max;
  47   int _tot;
  48   GrowableArray<int>* _elements;
  49 
  50 public:
  51   // Create a new, empty table.  "est" is an estimate of the maximum outcome
  52   // that will be added, and "max" is an outcome such that all outcomes at
  53   // least that large will be bundled with it.
  54   IntHistogram(int est, int max);
  55   // Add a measurement with the given outcome to the sequence.
  56   void add_entry(int outcome);
  57   // Return the number of entries recorded so far with the given outcome.
  58   int  entries_for_outcome(int outcome);
  59   // Return the total number of entries recorded so far.
  60   int  total_entries() { return _tot; }
  61   // Return the number of entries recorded so far with the given outcome as
  62   // a fraction of the total number recorded so far.
  63   double fraction_for_outcome(int outcome) {
  64     return
  65       (double)entries_for_outcome(outcome)/
  66       (double)total_entries();
  67   }
  68   // Print the histogram on the given output stream.
  69   void print_on(outputStream* st) const;
  70 };