add numerical recipes library

lib/nr/ansi/examples/xfactrl.c

@@ -0,0 +1,41 @@
+
+/* Driver for routine factrl */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define MAXSTR 80
+
+int main(void)
+{
+	char txt[MAXSTR];
+	float actual;
+	int i,n,nval;
+	FILE *fp;
+
+	if ((fp = fopen("fncval.dat","r")) == NULL)
+		nrerror("Data file fncval.dat not found\n");
+	fgets(txt,MAXSTR,fp);
+	while (strncmp(txt,"N-factorial",11)) {
+		fgets(txt,MAXSTR,fp);
+		if (feof(fp)) nrerror("Data not found in fncval.dat\n");
+	}
+	fscanf(fp,"%d %*s",&nval);
+	printf("\n%s\n",txt);
+	printf("%6s %18s %20s \n","n","actual","factrl(n)");
+	for (i=1;i<=nval;i++) {
+		fscanf(fp,"%d %f ",&n,&actual);
+		if (actual < 1.0e10)
+			printf("%6d %20.0f %20.0f\n",n,actual,factrl(n));
+		else
+			printf("%6d %20e %20e \n",n,actual,factrl(n));
+	}
+	fclose(fp);
+	return 0;
+}
+#undef NRANSI