protect week.hpp against double-inclusion

diff --git a/src/week.hpp b/src/week.hpp
index e50f7b8..a377ac6 100644 (file)
--- a/src/week.hpp
+++ b/src/week.hpp
@@ -7,6 +7,9 @@
  *
  */
 
+#ifndef __WEEK_HPP
+#define __WEEK_HPP
+
 #include <string>
 #include <bitset>
 
@@ -130,3 +133,5 @@ inline Week operator^(const Week& lhs, const Week& rhs)
 
 }
 }
+
+#endif