10.7 Programming Exercises

Note that the solutions to all the exercises below can be obtained using standard C++ syntax such as inline and enum. In general, using C++ construction is preferred over using macro definitions. However since this is the chapter on the preprocessor, macros should be used for these exercises.

Exercise 10-1: Create a set of macros to define a type called RETURN_STATUS and the following values: RETURN_SUCCESS, RETURN_WARNING, and RETURN_ERROR. Define a macro, CHECK_RETURN_FATAL,,, that takes a RETURN_STATUS as its argument and returns true if you have a fatal error.

Exercise 10-2: Write a macro that returns true if its parameter is divisible by 10 and false otherwise.

Exercise 10-3: Write a macro is_digit that returns true if its argument is a decimal digit. Write a second macro is_hex that returns true if its argument is a hex digit (0-9, A-F, a-f). The second macro should reference the first.

Exercise 10-4: Write a preprocessor macro that swaps two integers. (If you're a real hacker, write one that does not use a temporary variable declared outside the macro.)