diff --git a/example/array_ex.cpp b/example/array_ex.cpp
index 9f4ab9f..9729e6f 100644
--- a/example/array_ex.cpp
+++ b/example/array_ex.cpp
@@ -30,6 +30,11 @@
 
 using namespace gctl;
 
+double get_x(const point3dc &p)
+{
+	return p.x;
+}
+
 int main(int argc, char const *argv[]) try
 {
 	// create a new array and give initial values
@@ -64,7 +69,8 @@ int main(int argc, char const *argv[]) try
 	P.sequence(point3dc(0, 0, 0), point3dc(2, 1, 0.5));
 	P.show(std::cout, '\n');
 
-	array<double> Px = P.extract<double>([](const point3dc &p)->double{return p.x;});
+	//array<double> Px = P.extract<double>([](const point3dc &p)->double{return p.x;});
+	array<double> Px = P.extract<double>(get_x);
 	Px.show();
 
 	// create a new 2D array