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/*****************************************************************************/
/* statistics.c */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* Standalone library for calculating median and mode of a data set. */
/* (c) 2001, 2004, Pal, A. (apal@szofi.elte.hu). */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* See function prototypes and the usage of the functions in statistics.h */
/*****************************************************************************/
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include "statistics.h"
/*****************************************************************************/
static int median_compare(const void *px,const void *py)
{
if ( *(double *)px < *(double *)py ) return(-1);
else return(1);
}
double median(double *data,int n)
{
double m;
if ( data==NULL || n<=0 )
return(0.0);
qsort((void *)data,n,sizeof(double),median_compare);
if ( n%2 ) m=data[n/2];
else m=0.5*(data[n/2-1]+data[n/2]);
return(m);
}
/*****************************************************************************/
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