diff --git a/examples/helloworld.cc b/examples/helloworld.cc
index 9e32fad..40c2f2c 100644
--- a/examples/helloworld.cc
+++ b/examples/helloworld.cc
@@ -1,5 +1,5 @@
 // Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2015 Google Inc. All rights reserved.
+// Copyright 2023 Google Inc. All rights reserved.
 // http://ceres-solver.org/
 //
 // Redistribution and use in source and binary forms, with or without
@@ -36,12 +36,6 @@
 #include "ceres/ceres.h"
 #include "glog/logging.h"
 
-using ceres::AutoDiffCostFunction;
-using ceres::CostFunction;
-using ceres::Problem;
-using ceres::Solve;
-using ceres::Solver;
-
 // A templated cost functor that implements the residual r = 10 -
 // x. The method operator() is templated so that we can then use an
 // automatic differentiation wrapper around it to generate its
@@ -63,19 +57,19 @@
   const double initial_x = x;
 
   // Build the problem.
-  Problem problem;
+  ceres::Problem problem;
 
   // Set up the only cost function (also known as residual). This uses
   // auto-differentiation to obtain the derivative (jacobian).
-  CostFunction* cost_function =
-      new AutoDiffCostFunction<CostFunctor, 1, 1>(new CostFunctor);
+  ceres::CostFunction* cost_function =
+      new ceres::AutoDiffCostFunction<CostFunctor, 1, 1>();
   problem.AddResidualBlock(cost_function, nullptr, &x);
 
   // Run the solver!
-  Solver::Options options;
+  ceres::Solver::Options options;
   options.minimizer_progress_to_stdout = true;
-  Solver::Summary summary;
-  Solve(options, &problem, &summary);
+  ceres::Solver::Summary summary;
+  ceres::Solve(options, &problem, &summary);
 
   std::cout << summary.BriefReport() << "\n";
   std::cout << "x : " << initial_x << " -> " << x << "\n";