add numerical recipes library

lib/nr/ansi/recipes/badluk.c

@@ -0,0 +1,52 @@
+
+#include <stdio.h>
+#include <math.h>
+#define ZON -5.0
+#define IYBEG 1900
+#define IYEND 2000
+
+int main(void)  /* Program badluk */
+{
+	void flmoon(int n, int nph, long *jd, float *frac);
+	long julday(int mm, int id, int iyyy);
+	int ic,icon,idwk,im,iyyy,n;
+	float timzon = ZON/24.0,frac;
+	long jd,jday;
+
+	printf("\nFull moons on Friday the 13th from %5d to %5d\n",IYBEG,IYEND);
+	for (iyyy=IYBEG;iyyy<=IYEND;iyyy++) {
+		for (im=1;im<=12;im++) {
+			jday=julday(im,13,iyyy);
+			idwk=(int) ((jday+1) % 7);
+			if (idwk == 5) {
+				n=(int)(12.37*(iyyy-1900+(im-0.5)/12.0));
+				icon=0;
+				for (;;) {
+					flmoon(n,2,&jd,&frac);
+					frac=24.0*(frac+timzon);
+					if (frac < 0.0) {
+						--jd;
+						frac += 24.0;
+					}
+					if (frac > 12.0) {
+						++jd;
+						frac -= 12.0;
+					} else
+						frac += 12.0;
+					if (jd == jday) {
+						printf("\n%2d/13/%4d\n",im,iyyy);
+						printf("%s %5.1f %s\n","Full moon",frac,
+							" hrs after midnight (EST)");
+						break;
+					} else {
+						ic=(jday >= jd ? 1 : -1);
+						if (ic == (-icon)) break;
+						icon=ic;
+						n += ic;
+					}
+				}
+			}
+		}
+	}
+	return 0;
+}