extract ScInterpreter::div to own method

we need that method soon in another place

Change-Id: Ic5b20acd666bd4d5183be7acc9d9ebe2c0a810f7

sc/inc/math.hxx

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef __INCLUDED_SC_INC_MATH_HXX__
+#define __INCLUDED_SC_INC_MATH_HXX__
+
+#include <formula/errorcodes.hxx>
+
+namespace sc {
+
+inline double div( const double& fNumerator, const double& fDenominator )
+{
+    return (fDenominator != 0.0) ? (fNumerator / fDenominator) :
+        CreateDoubleError( errDivisionByZero);
+}
+
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

sc/source/core/inc/interpre.hxx

@@ -31,6 +31,7 @@
 #include "externalrefmgr.hxx"
 #include "calcconfig.hxx"
 #include "token.hxx"
+#include "math.hxx"
 
 #include <map>
 #include <vector>
@@ -1002,8 +1003,7 @@ inline void ScInterpreter::TreatDoubleError( double& rVal )
 
 inline double ScInterpreter::div( const double& fNumerator, const double& fDenominator )
 {
-    return (fDenominator != 0.0) ? (fNumerator / fDenominator) :
-        CreateDoubleError( errDivisionByZero);
+    return sc::div(fNumerator, fDenominator);
 }
 
 inline sal_Int16 ScInterpreter::GetDayOfWeek( sal_Int32 n )