made some final changes to the comments

String.cpp

@@ -151,8 +151,9 @@ std::istream& operator>>(std::istream& is, String& str)
 {
     constexpr size_t BUFSIZE = 50;                // set some reasonable buffer size
     char buf[BUFSIZE];
-    std::unique_ptr<char[]> data(new char[1]);    // istream data - I use unique_ptr for exception safety
+    std::unique_ptr<char[]> data(new char[1]);    // istream data - unique_ptr for exception safety
     data.get()[0] = '\0';                         // init it with a null terminator
+
     while (is.get(buf, BUFSIZE))                  // while there is still some data in the stream
     {
         std::unique_ptr<char[]> newdata(new char[strlen(data.get()) + BUFSIZE]);    // make some space
@@ -160,6 +161,7 @@ std::istream& operator>>(std::istream& is, String& str)
         data.swap(newdata);                       // make the old data go out of scope instead of newdata
         std::strcat(data.get(), buf);             // append new input
     }
+
     std::unique_ptr<char[]> newdata(new char[strlen(data.get()) + 1]);              // shrink the array
     std::strcpy(newdata.get(), data.get());                                         // to fit the data
     data.swap(newdata);

StringValue.cpp

@@ -28,7 +28,7 @@ const char& StringValue::operator[](size_t index) const
     return _data[index];
 }
 
-// reuse const operator[], just as Scott Meyers would
+// reuse const operator[]
 char& StringValue::operator[](size_t index)
 { return const_cast<char&>(const_cast<const StringValue*>(this)->operator[](index)); }
 

manualtest.cpp

@@ -7,7 +7,8 @@
 
 
 /* This is a demonstration, that the String class and it's components work
- * correctly, basically a non-unit test. Perfect for usage with valgrind */
+ * correctly, basically a non-unit test. Perfect for usage with valgrind.
+ * Note that these tests are only used in case GTest is not present on the system. */
 int main()
 {
     if (std::is_default_constructible<String>::value)

test.cpp

@@ -10,7 +10,8 @@
 
 
 /* These unit tests were written using the Google Test framework,
- * and check everything stated in the specification. */
+ * and check everything stated in the specification. Note that
+ * these tests are only used in case GTest is present on the system.*/
 ///////////////////////////////////////////////////////////////
 ///                Testing helper classes                   ///
 ///////////////////////////////////////////////////////////////