1 files changed, 55 insertions, 0 deletions
diff --git a/randnum.c b/randnum.c
new file mode 100644
index 0000000..7d2620f
--- /dev/null
+++ b/randnum.c
@@ -0,0 +1,55 @@
+#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));
+}
+