diff --git a/ex4.2/CaloGrid.cc b/ex4.2/CaloGrid.cc
index 3c52230..bc4f79a 100644
--- a/ex4.2/CaloGrid.cc
+++ b/ex4.2/CaloGrid.cc
@@ -13,6 +13,6 @@ CaloCell* CaloGrid::cell(int x, int y ) {
 		return nullptr;
 	}
 
-	return cells[ x * nx + y ] ;
+	return &cells[ x*nx + y ] ;
 }
 
diff --git a/ex4.2/CaloGrid.hh b/ex4.2/CaloGrid.hh
index ed1da6b..f9dd737 100644
--- a/ex4.2/CaloGrid.hh
+++ b/ex4.2/CaloGrid.hh
@@ -25,6 +25,9 @@ class CaloGrid
 		}
 
 		CaloCell* cell(int x, int y);
+		const CaloCell* cell(int x, int y) const {
+			return const_cast<CaloCell*> (cell(x, y));
+		}
 
 
 	private: