add numerical recipes library

lib/nr/ansi/examples/xdecchk.c

@@ -0,0 +1,59 @@
+
+/* Driver for routine decchk */
+
+#include <stdio.h>
+#define NRANSI
+#include "nr.h"
+
+#define MAXLINE 128
+
+int main(void)
+{
+	int j,k,l,n,nbad=0,ntot=0;
+	int iok,jok;
+	char lin[MAXLINE+2],ch,chh;
+
+	/* test all jump transpositions of the form 86jlk41 */
+	lin[0]='8';
+	lin[1]='6';
+	lin[5]='4';
+	lin[6]='1';
+	for (j=48;j<=57;j++) {
+		for (k=48;k<=57;k++) {
+			for (l=48;l<=57;l++) {
+				lin[3]=l;
+				if (j != k) {
+					ntot++;
+					lin[2]=j;
+					lin[4]=k;
+					iok=decchk(lin,7,&ch);
+					lin[7]=ch;
+					iok=decchk(lin,8,&chh);
+					lin[2]=k;
+					lin[4]=j;
+					jok=decchk(lin,8,&chh);
+					if (!iok || jok) nbad++;
+				}
+			}
+		}
+	}
+	printf("%s %14s %3d\n","Total tries:"," ",ntot);
+	printf("%s %16s %3d\n","Bad tries:"," ",nbad);
+	printf("%s %11s %4.2f\n","Fraction good:"," ",((float)(ntot-nbad))/ntot);
+	for (;;) {
+		printf("enter string terminated by x:\n");
+		if (gets(lin) == NULL) break;
+		for (j=0;j<MAXLINE;j++)
+			if (lin[j] == 'x') break;
+		n=j;
+		if (!n) break;
+		iok=decchk(lin,n,&ch);
+		lin[n]=ch;
+		jok=decchk(lin,n+1,&chh);
+		lin[n+1]=0;
+		printf("%s checks as %c\n",lin,jok ? 'T' : 'F');
+	}
+	printf("Normal completion\n");
+	return 0;
+}
+#undef NRANSI