/* DataSet.h
   Specification of a DataSet Class
   [Taken from requirements .....]
   Author: J Morris
   Date Last Modified: 17 October, 1997
*/

typedef struct dataset *DataSet;

DataSet ConsDataSet( int max_items );
/* Construct a new data set -
   max_items is the maximum number of points in the data set
   Pre-cond: max_items > 0
   Post-cond: returns a newly constructed DataSet 
               or
              NULL if insufficient memory
*/

int DeleteDataSet( DataSet ds );
/* Delete a data set.
   Pre-cond: ds is a valid DataSet
   Post-cond: space used by ds has been freed
              returns TRUE if no errors, FALSE on error
*/

int ClearDataSet( DataSet ds );
/* Reset the DataSet ds
   (allows the same space to be re-used, without 
    free/malloc overhead)
   Pre-cond: ds is a valid DataSet
   Post-cond: entries in ds have all been cleared,
*/

int TotalPoints( DataSet ds );
/* Count total points in the data set
   Pre-cond: ds is a valid DataSet
   Post-cond: returns count of points added to the DataSet
*/

int AddDatum( DataSet ds, double x );
/* Add a new data point to the data set
   Pre-cond: ds is a valid DataSet
   Post-cond: TotalPoints( h ) = old TotalPoints( h ) + 1
*/
   
double SampleMean( DataSet ds, int *num_below );
/* Return the sample mean and the number of items below the
   mean in the int to which num_below points
   Pre-cond: ds is a valid DataSet && num_below is a valid pointer
   Post-cond: returns the mean of the data points added so far
*/ 

double Maximum( DataSet ds, int *index );
double Minimum( DataSet ds, int *index );
/* Return the maximum/minimum value in the data set 
   Pre-cond: ds is a valid DataSet
             index != NULL
   Post-cond: returns the maximum/minimum
              index points to the 'position' of the maximum/minimum
*/