From 11b1c6e94d9f8ba278b53b07c47fc3a5481d94c3 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Tue, 9 Jul 2024 15:14:26 -0600
Subject: [PATCH] Read input file name from the command line.

---
 examples/step-86/step-86.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/examples/step-86/step-86.cc b/examples/step-86/step-86.cc
index 4dd5daac1a..cc54612330 100644
--- a/examples/step-86/step-86.cc
+++ b/examples/step-86/step-86.cc
@@ -1115,8 +1115,10 @@ int main(int argc, char **argv)
 
       Utilities::MPI::MPI_InitFinalize mpi_initialization(argc, argv, 1);
       HeatEquation<2>                  heat_equation_solver(MPI_COMM_WORLD);
-      ParameterAcceptor::initialize("heat_equation.prm",
-                                    "heat_equation_used.prm");
+
+      const std::string input_filename =
+        (argc > 1 ? argv[1] : "heat_equation.prm");
+      ParameterAcceptor::initialize(input_filename, "heat_equation_used.prm");
       heat_equation_solver.run();
     }
   catch (std::exception &exc)
-- 
2.39.5