******** fig10.55 **********

	unsigned int seed;	/* global variable */

	#define a	16807		/* 7^5 */
	#define m	2147483647	/* 2^31 - 1*/
	#define q	127773		/* m/a */
	#define r	2836		/* m%a */

	double
	random( void )
	{
		int tmp_seed;
	
		tmp_seed = a * ( seed % q ) - r * (seed / q );
		if( tmp_seed >= 0 )
			seed = tmp_seed;
		else
			seed = tmp_seed + m;

		return( ( (double) seed ) / m );
	}