add numerical recipes library

lib/nr/ansi/examples/xsort3.c

@@ -0,0 +1,59 @@
+
+/* Driver for routine sort3 */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#define NRANSI
+#include "nr.h"
+#include "nrutil.h"
+
+#define NLEN 64
+
+int main(void)
+{
+	int i,j;
+	char dummy[NLEN],amsg[NLEN+1],bmsg[NLEN+1],cmsg[NLEN+1];
+	float *a,*b,*c;
+	FILE *fp;
+
+	a=vector(1,NLEN);
+	b=vector(1,NLEN);
+	c=vector(1,NLEN);
+	(void) strcpy(amsg,"I'd rather have a bottle in front of");
+	(void) strcat(amsg," me than a frontal lobotomy.");
+	printf("\noriginal message:\n%s\n",amsg);
+	/* read array of random numbers */
+	if ((fp = fopen("tarray.dat","r")) == NULL)
+		nrerror("Data file tarray.dat not found\n");
+	fgets(dummy,NLEN,fp);
+	for (i=1;i<=NLEN;i++) fscanf(fp,"%f",&a[i]);
+	fclose(fp);
+	/* create array b and array c */
+	for (i=1;i<=NLEN;i++) {
+		b[i]=i;
+		c[i]=NLEN+1-i;
+	}
+	/* sort array a while mixing b and c */
+	sort3(NLEN,a,b,c);
+	/* scramble message according to array b */
+	bmsg[NLEN]=amsg[NLEN];  /* null terminating character */
+	for (i=1;i<=NLEN;i++) {
+		j=b[i];
+		bmsg[i-1]=amsg[j-1];
+	}
+	printf("\nscrambled message:\n%s\n",bmsg);
+	/* unscramble according to array c */
+	cmsg[NLEN]=amsg[NLEN];
+	for (i=1;i<=NLEN;i++) {
+		j=c[i];
+		cmsg[j-1]=bmsg[i-1];
+	}
+	printf("\nmirrored message:\n%s\n",cmsg);
+	free_vector(c,1,NLEN);
+	free_vector(b,1,NLEN);
+	free_vector(a,1,NLEN);
+	return 0;
+}
+#undef NRANSI