diff --git a/NPLib/GASPARD/TGaspardTrackerPhysics.cxx b/NPLib/GASPARD/TGaspardTrackerPhysics.cxx
index 69340326c2729b8bce3648219ee9ec5a21d2e900..ac7dd1823d5e5fc680d668a867186153ad86c00b 100644
--- a/NPLib/GASPARD/TGaspardTrackerPhysics.cxx
+++ b/NPLib/GASPARD/TGaspardTrackerPhysics.cxx
@@ -23,7 +23,9 @@
 
 #include "TGaspardTrackerPhysics.h"
 #include <iostream>
+#include <cstdlib>
 
+using namespace std ;
 
 ClassImp(TGaspardTrackerPhysics)