Cancelling std::cout code lines using preprocessor

Question

One can remove all calls to printf() using #define printf. What if I have a lot of debug prints like std::cout << x << endl; ? How can I quickly switch off cout << statements in a single file using preprocessor?

Answer 1

As "unwind" already said, the quick solution is a do-nothing stream. There are better implementations though:

class NullStream {
    public:
    NullStream() { }
    template<typename T> NullStream& operator<<(T const&) { return *this; }
};

You still have a slight issue with std::cout since that's a sequence of three tokens, and you really don't want to redefine std or cout individually. A simple solution is

#ifdef NDEBUG
    #define COUT std::cout
#else
    #define COUT NullStream()
#endif

COUT << "Hello, world" << std::endl;

Answer 2

As a general principle logging to stdout should be avoided - far better to log to a logfile, and then you can use standard configuration tools to change log levels, or turn it off altogether.

Just my $0.02.....