1 files changed, 3 insertions, 2 deletions
diff --git a/src/Persistent_cohomology/example/exact_alpha_complex_3d_persistence.cpp b/src/Persistent_cohomology/example/exact_alpha_complex_3d_persistence.cpp
index acb34bcb..09561d03 100644
--- a/src/Persistent_cohomology/example/exact_alpha_complex_3d_persistence.cpp
+++ b/src/Persistent_cohomology/example/exact_alpha_complex_3d_persistence.cpp
@@ -77,8 +77,9 @@ using Simplex_tree_vector_vertex = std::vector< Simplex_tree_vertex >;
 using PCOH = Gudhi::persistent_cohomology::Persistent_cohomology< ST, Gudhi::persistent_cohomology::Field_Zp >;
 
 void usage(char * const progName) {
-  std::cerr << "Usage: " << progName <<
-      " path_to_file_graph coeff_field_characteristic[integer > 0] min_persistence[float >= -1.0]\n";
+  std::cerr << "Usage:\n" << progName << " path_to_OFF_file coeff_field_characteristic[integer " <<
+               "> 0] min_persistence[float >= -1.0]\n";
+  std::cerr << "  path_to_OFF_file is the path to your points cloud in OFF format.\n";
   exit(-1);
 }