diff --git a/src/cmlib-example/main.cpp b/src/cmlib-example/main.cpp
index 5cc645f..f016ec8 100644
--- a/src/cmlib-example/main.cpp
+++ b/src/cmlib-example/main.cpp
@@ -3,6 +3,18 @@
 #include <QCoreApplication>
 #include <QDebug>
 
+// function args by ref
+int sum(QStringList sl)
+{
+	int s = 0;
+	for(auto str: sl)
+	{
+		s += str.toInt();
+	}
+	return s;
+}
+
+
 int main( int argc, char** argv )
 {
 	QCoreApplication app( argc, argv );
@@ -17,10 +29,20 @@ int main( int argc, char** argv )
 
 	// loop add ref
 	QStringList sl;
-	for (auto s: sl)
+	sl << "111" << "222" << "333";
+	for (const auto &s: sl)
 	{
 		qDebug() << s;
 	}
 
+	// loop qasconst
+	for (auto s: sl)
+	{
+		s.append("0");
+	}
+
+	// function args by ref
+	auto ir = sum(sl);
+
 	return( 0 );
 }