add numerical recipes library

lib/nr/k_and_r/recipes/fourew.c

@@ -0,0 +1,20 @@
+
+#include <stdio.h>
+#define SWAP(a,b) ftemp=(a);(a)=(b);(b)=ftemp
+
+void fourew(file,na,nb,nc,nd)
+FILE *file[5];
+int *na,*nb,*nc,*nd;
+{
+	int i;
+	FILE *ftemp;
+
+	for (i=1;i<=4;i++) rewind(file[i]);
+	SWAP(file[2],file[4]);
+	SWAP(file[1],file[3]);
+	*na=3;
+	*nb=4;
+	*nc=1;
+	*nd=2;
+}
+#undef SWAP