add numerical recipes library

lib/nr/ansi/examples/xflmoon.c

@@ -0,0 +1,54 @@
+
+/* Driver for routine flmoon */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+
+#define ZON (-5.0)
+
+int main(void)
+{
+	int i,i1,i2,i3,id,im,iy,n,nph=2;
+	float timzon=ZON/24.0,frac,secs;
+	long j1,j2;
+	static char *phase[]={"new moon","first quarter",
+		"full moon","last quarter"};
+
+	printf("Date of the next few phases of the moon\n");
+	printf("Enter today\'s date (e.g. 12 15 1992)  :  \n");
+	scanf("%d %d %d",&im,&id,&iy);
+	/* Approximate number of full moons since january 1900 */
+	n=(int)(12.37*(iy-1900+((im-0.5)/12.0)));
+	j1=julday(im,id,iy);
+	flmoon(n,nph,&j2,&frac);
+	n += (int) ((j1-j2)/29.53 + (j1 >= j2 ? 0.5 : -0.5));
+	printf("\n%10s %19s %9s\n","date","time(EST)","phase");
+	for (i=1;i<=20;i++) {
+		flmoon(n,nph,&j2,&frac);
+		frac=24.0*(frac+timzon);
+		if (frac < 0.0) {
+			--j2;
+			frac += 24.0;
+		}
+		if (frac > 12.0) {
+			++j2;
+			frac -= 12.0;
+		} else
+			frac += 12.0;
+		i1=(int) frac;
+		secs=3600.0*(frac-i1);
+		i2=(int) (secs/60.0);
+		i3=(int) (secs-60*i2+0.5);
+		caldat(j2,&im,&id,&iy);
+		printf("%5d %3d %5d %7d:%2d:%2d      %s\n",
+			im,id,iy,i1,i2,i3,phase[nph]);
+		if (nph == 3) {
+			nph=0;
+			++n;
+		} else
+			++nph;
+	}
+	return 0;
+}
+#undef NRANSI