add numerical recipes library

lib/nr/cpp/recipes/badluk.cpp

@@ -0,0 +1,53 @@
+#include <iostream>
+#include <iomanip>
+#include <cmath>
+#include "nr.h"
+using namespace std;
+
+int main(void)	// Program badluk
+{
+	const int IYBEG=2000,IYEND=2100;
+	const DP ZON=-5.0;
+	int ic,icon,idwk,im,iyyy,jd,jday,n;
+	DP timzon=ZON/24.0,frac;
+
+	cout << endl << "Full moons on Friday the 13th from ";
+	cout << setw(5) << IYBEG << " to " << setw(5) << IYEND << endl;
+	for (iyyy=IYBEG;iyyy<=IYEND;iyyy++) {
+		for (im=1;im<=12;im++) {
+			jday=NR::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 (;;) {
+					NR::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) {
+						cout << endl << setw(2) << im;
+						cout << "/13/" << setw(4) << iyyy << endl;
+						cout << fixed << setprecision(1);
+						cout << "Full moon" << setw(6) << frac;
+						cout << " hrs after midnight (EST)" << endl;
+						break;
+					} else {
+						ic=(jday >= jd ? 1 : -1);
+						if (ic == (-icon)) break;
+						icon=ic;
+						n += ic;
+					}
+				}
+			}
+		}
+	}
+	return 0;
+}