Use the correct file extension.

diff --git a/examples/step-15/step-15.cc b/examples/step-15/step-15.cc
index 86b0674c64037ebb9629f18bff5b0b8251c8469d..eeab634d80074057346dcb1f14bbb788340ead67 100644 (file)
--- a/examples/step-15/step-15.cc
+++ b/examples/step-15/step-15.cc
@@ -660,7 +660,7 @@ namespace Step15
         data_out.build_patches();
 
         const std::string filename =
-          "solution-" + Utilities::int_to_string(refinement_cycle, 2) + ".vtk";
+          "solution-" + Utilities::int_to_string(refinement_cycle, 2) + ".vtu";
         std::ofstream output(filename);
         data_out.write_vtu(output);