diff --git a/OndselSolver/ASMTAssembly.h b/OndselSolver/ASMTAssembly.h
index 4875f82..91b575b 100644
--- a/OndselSolver/ASMTAssembly.h
+++ b/OndselSolver/ASMTAssembly.h
@@ -83,7 +83,7 @@ namespace MbD {
 		double calcCharacteristicLength();
 		std::shared_ptr<std::vector<std::shared_ptr<ASMTItemIJ>>> connectorList();
 		std::shared_ptr<std::map<std::string, std::shared_ptr<ASMTMarker>>>markerMap();
-		void deleteMbD();
+		void deleteMbD() override;
 		void createMbD(std::shared_ptr<System> mbdSys, std::shared_ptr<Units> mbdUnits) override;
 		void outputFile(std::string filename);
 		void storeOnLevel(std::ofstream& os, int level) override;
diff --git a/OndselSolver/AccNewtonRaphson.h b/OndselSolver/AccNewtonRaphson.h
index 469994d..b304629 100644
--- a/OndselSolver/AccNewtonRaphson.h
+++ b/OndselSolver/AccNewtonRaphson.h
@@ -22,7 +22,7 @@ namespace MbD {
         void incrementIterNo() override;
         void initializeGlobally() override;
         void logSingularMatrixMessage();
-        void passRootToSystem();
+        void passRootToSystem() override;
         void postRun() override;
         void preRun() override;
         void handleSingularMatrix() override;
diff --git a/OndselSolver/DispCompIeqcJeqcKeqct.h b/OndselSolver/DispCompIeqcJeqcKeqct.h
index 40f264a..b555101 100644
--- a/OndselSolver/DispCompIeqcJeqcKeqct.h
+++ b/OndselSolver/DispCompIeqcJeqcKeqct.h
@@ -21,13 +21,13 @@ namespace MbD {
         void calcPostDynCorrectorIteration() override;
         void initialize() override;
         void initializeGlobally() override;
-        FRowDsptr ppvaluepXIpt();
-        FRowDsptr ppvaluepEIpt();
-        FRowDsptr ppvaluepEKpt();
-        FRowDsptr ppvaluepXJpt();
-        FRowDsptr ppvaluepEJpt();
-        double ppvalueptpt();
-        double pvaluept();
+        FRowDsptr ppvaluepXIpt() override;
+        FRowDsptr ppvaluepEIpt() override;
+        FRowDsptr ppvaluepEKpt() override;
+        FRowDsptr ppvaluepXJpt() override;
+        FRowDsptr ppvaluepEJpt() override;
+        double ppvalueptpt() override;
+        double pvaluept() override;
         void preAccIC() override;
         void preVelIC() override;
 
diff --git a/OndselSolver/DispCompIeqctJeqcO.h b/OndselSolver/DispCompIeqctJeqcO.h
index 01b1e33..4a56ba5 100644
--- a/OndselSolver/DispCompIeqctJeqcO.h
+++ b/OndselSolver/DispCompIeqctJeqcO.h
@@ -24,7 +24,7 @@ namespace MbD {
         double ppvalueptpt() override;
         void preAccIC() override;
         void preVelIC() override;
-        double pvaluept();
+        double pvaluept() override;
 
         double priIeJeOpt;
         FRowDsptr ppriIeJeOpEIpt;
diff --git a/OndselSolver/FullMatrix.h b/OndselSolver/FullMatrix.h
index bc954b5..761224a 100644
--- a/OndselSolver/FullMatrix.h
+++ b/OndselSolver/FullMatrix.h
@@ -85,7 +85,7 @@ namespace MbD {
 		FMatsptr<T> transpose();
 		FMatsptr<T> negated();
 		void symLowerWithUpper();
-		void atiput(int i, FRowsptr<T> fullRow);
+		void atiput(int i, FRowsptr<T> fullRow) override;
 		void atijput(int i, int j, T value);
 		void atijputFullColumn(int i, int j, FColsptr<T> fullCol);
 		void atijplusFullRow(int i, int j, FRowsptr<T> fullRow);
diff --git a/OndselSolver/GESpMat.h b/OndselSolver/GESpMat.h
index fb24492..517ea82 100644
--- a/OndselSolver/GESpMat.h
+++ b/OndselSolver/GESpMat.h
@@ -16,7 +16,7 @@ namespace MbD {
     {
         //markowitzPivotRowCount markowitzPivotColCount privateIndicesOfNonZerosInPivotRow rowPositionsOfNonZerosInPivotColumn 
     public:
-        FColDsptr solvewithsaveOriginal(SpMatDsptr spMat, FColDsptr fullCol, bool saveOriginal);
+        FColDsptr solvewithsaveOriginal(SpMatDsptr spMat, FColDsptr fullCol, bool saveOriginal) override;
         FColDsptr basicSolvewithsaveOriginal(SpMatDsptr spMat, FColDsptr fullCol, bool saveOriginal) override;
         FColDsptr basicSolvewithsaveOriginal(FMatDsptr fullMat, FColDsptr fullCol, bool saveOriginal) override;
         void preSolvewithsaveOriginal(FMatDsptr fullMat, FColDsptr fullCol, bool saveOriginal) override;
diff --git a/OndselSolver/Item.h b/OndselSolver/Item.h
index 8ab95f8..79a5690 100644
--- a/OndselSolver/Item.h
+++ b/OndselSolver/Item.h
@@ -151,13 +151,14 @@ namespace MbD {
 		virtual std::ostream& printOn(std::ostream& s) const;
 		friend std::ostream& operator<<(std::ostream& s, const Item& item)
 		{
-			if (&item) {
+            // the following if cannot be false
+//			if (&item) {
 				return item.printOn(s);
-			}
-			else {
-				s << "NULL";
-			}
-			return s;
+//			}
+//			else {
+//				s << "NULL";
+//			}
+			//return s;
 		}
 
 		std::string name;
diff --git a/OndselSolver/RowTypeMatrix.h b/OndselSolver/RowTypeMatrix.h
index 86b799b..9e0efd5 100644
--- a/OndselSolver/RowTypeMatrix.h
+++ b/OndselSolver/RowTypeMatrix.h
@@ -21,7 +21,7 @@ namespace MbD {
 		RowTypeMatrix(int m) : Array<T>(m) {}
 		RowTypeMatrix(std::initializer_list<T> list) : Array<T>{ list } {}
 		void copyFrom(std::shared_ptr<RowTypeMatrix<T>> x);
-		virtual void zeroSelf() = 0;
+		virtual void zeroSelf() override = 0;
 		//double maxMagnitude() override;
 		int numberOfElements() override;
 
diff --git a/OndselSolver/SparseMatrix.h b/OndselSolver/SparseMatrix.h
index 44e18c1..22276c2 100644
--- a/OndselSolver/SparseMatrix.h
+++ b/OndselSolver/SparseMatrix.h
@@ -40,7 +40,7 @@ namespace MbD {
 				this->push_back(row);
 			}
 		}
-		void atiput(int i, SpRowsptr<T> spRow);
+		void atiput(int i, SpRowsptr<T> spRow) override;
 		void atijplusDiagonalMatrix(int i, int j, DiagMatDsptr diagMat);
 		void atijminusDiagonalMatrix(int i, int j, DiagMatDsptr diagMat);
 		double sumOfSquares() override;
diff --git a/OndselSolver/SystemNewtonRaphson.h b/OndselSolver/SystemNewtonRaphson.h
index aea3d36..1cfedd7 100644
--- a/OndselSolver/SystemNewtonRaphson.h
+++ b/OndselSolver/SystemNewtonRaphson.h
@@ -19,7 +19,7 @@ namespace MbD {
         //
     public:
         void initializeGlobally() override;
-        virtual void assignEquationNumbers() = 0;
+        virtual void assignEquationNumbers() override = 0;
         virtual void createVectorsAndMatrices();
         std::shared_ptr<MatrixSolver> matrixSolverClassNew() override;
         void calcdxNorm() override;