added %e notation output for very small p

ztop.cc

@@ -61,7 +61,10 @@ for (i=2; i<argc; i++)
   if (twotailed)
     p*=2;
   
-  printf("%f\n",p);
+  if (p>0.000001) 
+    printf("%f\n",p);
+  else
+    printf("%e\n",p);
 
   return(0);
 }