#include <stdint.h>
#include <math.h>

/****************************
** RANDOM NUMBER GENERATOR **
*****************************
** This is a second-order linear congruential random number
** generator.  Its advantage is (of course) that it can be
** seeded and will thus produce repeatable sequences of
** random numbers.
*/

/****************************
*        randnum()          *
*****************************
** Second order linear congruential generator.
** Constants suggested by J. G. Skellam.
** If val==0, returns next member of sequence.
**    val!=0, restart generator.
*/

int32_t randnum(int32_t val) {
	static int32_t randw[2] = { 13 , 117 };
	int32_t interm;

	if (val != 0) {
		randw[0] = 13;
		randw[1] = 117;
	}

	interm = (randw[0]* (int32_t)254754 + randw[1]*(int32_t)529562) % (int32_t)999563;
	randw[1] = randw[0];
	randw[0] = interm;
	return(interm);
}

/****************************
*         randwc()          *
*****************************
** Returns signed 32-bit random modulo num.
*/
int32_t randwc(int32_t num) {
	return(randnum(0) % num);
}

/***************************
**      abs_randwc()      **
****************************
** Same as randwc(), only this routine returns only
** positive numbers.
*/
uint32_t abs_randwc(uint32_t num) {
	return abs(randwc(num));
}