DIPlib Documentation - ©1995-2013 Quantitative Imaging Group, Delft University of Technology.

# SortCompareFunction

Typedef for comparison function (sorting)

## SYNOPSIS

`#include "dip_sort.h"`

dip_Boolean (*dip_SortCompareFunction) ( data1, index1, data2, index2 )

## FUNCTION

A function of this type must be supplied to the sorting algorithms for data of arbitrary type. It should return `DIP_TRUE` if data1[index1] > data2[index2].

Example:

    dip_Boolean MyComplexCompare( void *data1, dip_int index1, void *data2, dip_int index2 )
    {
       dip_complex *cmplx1, *cmplx2;
       dip_float magnitude1, magnitude2;

       cmplx1 = data1;
       cmplx2 = data2;
       cmplx1 += index1;
       cmplx2 += index2;
       magnitude1 = sqrt( cmplx1->re * cmplx1->re + cmplx1->im * cmplx1->im );
       magnitude2 = sqrt( cmplx2->re * cmplx2->re + cmplx2->im * cmplx2->im );
       if ( magnitude1 > magnitude2 )
       {
          return( DIP_TRUE );
       }
       else
       {
          return( DIP_FALSE );
       }
    }

## ARGUMENTS

Data type | Name | Description
`void *` | `data1` | Pointer to first data array
`dip_int` | `index1` | Index to element in first data array
`void *` | `data2` | Pointer to second data array
`dip_int` | `index2` | Index to element in second data array

## SEE ALSO

General information about sorting

`SortAnything`, `QuickSortAnything`, `SortSwapFunction`