diff --git a/include/cppjieba/DictTrie.hpp b/include/cppjieba/DictTrie.hpp
index c2b5e058..7a779365 100644
--- a/include/cppjieba/DictTrie.hpp
+++ b/include/cppjieba/DictTrie.hpp
@@ -19,9 +19,6 @@
 #include "Trie.hpp"
 
 namespace cppjieba {
-
-const double MIN_DOUBLE = -3.14e+100;
-const double MAX_DOUBLE = 3.14e+100;
 const size_t DICT_COLUMN_NUM = 3;
 const char* const UNKNOWN_TAG = "";
 
diff --git a/include/cppjieba/SegmentTagged.hpp b/include/cppjieba/SegmentTagged.hpp
index 4d99a31a..6f461aa9 100644
--- a/include/cppjieba/SegmentTagged.hpp
+++ b/include/cppjieba/SegmentTagged.hpp
@@ -5,6 +5,8 @@
 
 namespace cppjieba {
 
+class DictTrie;
+
 class SegmentTagged : public SegmentBase{
  public:
   SegmentTagged() {
diff --git a/include/cppjieba/Utils.hpp b/include/cppjieba/Utils.hpp
index a501d5ea..9fa76d78 100644
--- a/include/cppjieba/Utils.hpp
+++ b/include/cppjieba/Utils.hpp
@@ -56,6 +56,9 @@ enum {
   LL_FATAL = 4,
 };
 
+const double MIN_DOUBLE = -3.14e+100;
+const double MAX_DOUBLE = 3.14e+100;
+
 static const char* const LOG_LEVEL_ARRAY[] = {"DEBUG", "INFO", "WARN", "ERROR", "FATAL"};
 static const char* const LOG_TIME_FORMAT = "%Y-%m-%d %H:%M:%S";