diff --git a/googletest/samples/sample3_unittest.cc b/googletest/samples/sample3_unittest.cc
index e093c25..b19416d 100644
--- a/googletest/samples/sample3_unittest.cc
+++ b/googletest/samples/sample3_unittest.cc
@@ -71,7 +71,7 @@
   // virtual void SetUp() will be called before each test is run.  You
   // should define it if you need to initialize the variables.
   // Otherwise, this can be skipped.
-  virtual void SetUp() {
+  void SetUp() override {
     q1_.Enqueue(1);
     q2_.Enqueue(2);
     q2_.Enqueue(3);
@@ -99,8 +99,8 @@
     ASSERT_EQ(q->Size(), new_q->Size());
 
     // Verifies the relationship between the elements of the two queues.
-    for ( const QueueNode<int> * n1 = q->Head(), * n2 = new_q->Head();
-          n1 != NULL; n1 = n1->next(), n2 = n2->next() ) {
+    for (const QueueNode<int>*n1 = q->Head(), *n2 = new_q->Head();
+         n1 != nullptr; n1 = n1->next(), n2 = n2->next()) {
       EXPECT_EQ(2 * n1->element(), n2->element());
     }
 
@@ -125,16 +125,16 @@
 // Tests Dequeue().
 TEST_F(QueueTestSmpl3, Dequeue) {
   int * n = q0_.Dequeue();
-  EXPECT_TRUE(n == NULL);
+  EXPECT_TRUE(n == nullptr);
 
   n = q1_.Dequeue();
-  ASSERT_TRUE(n != NULL);
+  ASSERT_TRUE(n != nullptr);
   EXPECT_EQ(1, *n);
   EXPECT_EQ(0u, q1_.Size());
   delete n;
 
   n = q2_.Dequeue();
-  ASSERT_TRUE(n != NULL);
+  ASSERT_TRUE(n != nullptr);
   EXPECT_EQ(2, *n);
   EXPECT_EQ(1u, q2_.Size());
   delete n;