diff --git a/googletest/samples/sample1.h b/googletest/samples/sample1.h
index 2c3e9f0..ba392cf 100644
--- a/googletest/samples/sample1.h
+++ b/googletest/samples/sample1.h
@@ -29,13 +29,13 @@
 
 // A sample program demonstrating using Google C++ testing framework.
 
-#ifndef GTEST_SAMPLES_SAMPLE1_H_
-#define GTEST_SAMPLES_SAMPLE1_H_
+#ifndef GOOGLETEST_SAMPLES_SAMPLE1_H_
+#define GOOGLETEST_SAMPLES_SAMPLE1_H_
 
 // Returns n! (the factorial of n).  For negative n, n! is defined to be 1.
 int Factorial(int n);
 
-// Returns true iff n is a prime number.
+// Returns true if and only if n is a prime number.
 bool IsPrime(int n);
 
-#endif  // GTEST_SAMPLES_SAMPLE1_H_
+#endif  // GOOGLETEST_SAMPLES_SAMPLE1_H_