#include <stdlib.h>
#include <stdio.h>

#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))

int numarray[] = {123, 145, 512, 627, 800, 933};

int numeric ( const int *p1, const int *p2 )
{
	return ( *p1 - *p2 );
}

int lookup ( int key )
{
	int *itemptr;

	/* The cast of (int(*)(const void *,const void*))
	   is needed to avoid a type mismatch error at
	   compile time */
	itemptr = bsearch ( &key, numarray, NELEMS ( numarray ),
	                    sizeof ( int ), ( int ( * ) ( const void *,const void * ) ) numeric );
	return ( itemptr != NULL );
}

int main ( void )
{
	if ( lookup ( 512 ) )
		printf ( "512 is in the table.\n" );
	else
		printf ( "512 isn't in the table.\n" );

	return 0;
}