diff --git a/STL_Extension/include/CGAL/Concatenate_iterator.h b/STL_Extension/include/CGAL/Concatenate_iterator.h
index 3c51f94ca08..17a7b92ef8d 100644
--- a/STL_Extension/include/CGAL/Concatenate_iterator.h
+++ b/STL_Extension/include/CGAL/Concatenate_iterator.h
@@ -54,8 +54,10 @@ class Concatenate_iterator
 
 public:
   Concatenate_iterator() : e1_(), i1_(), b2_(), i2_() {}
+  
   Concatenate_iterator(It1 e1, It2 b2, It1 i1)
     : e1_(e1), i1_(i1), b2_(b2), i2_(b2) {}
+
   Concatenate_iterator(It1 e1, It2 b2, It2 i2, int)
     : e1_(e1), i1_(e1), b2_(b2), i2_(i2) {}
 
@@ -115,6 +117,7 @@ class Concatenate_iterator
     std::size_t res = 0;
     while(other != *this){
       ++res;
+      ++other;
     }
     return res;
   }