I've recently converted some C code to a bit more native C++. This included changing printf() statements to std::cout statements. However, some printf()'s are rather lengthy and annoyingly long (and human-error-prone) to write in std::cout. Example (and this one is a short one):


printf("ERROR %d: %s: %s\n", event, origin ? origin : "?", fulltext.c_str());


std::cout << "ERROR " << event << ": " << origin ? origin : "?" << ": " << fulltext << "\n";

I personally find the first way much more clear and easier to write. What is the recommended way to do this in C++?

5 Years
Discussion Span
Last Post by mike_2000_17

Well you could just put a bit more "style" into it:

std::cout << "ERROR " << event 
          << ": "     << (origin ? origin : "?") 
          << ": "     << fulltext 
          << std::endl;

It takes more lines of code, but it is worth it in terms of clarity.

If you have code like this that gets repetitive, like an error report that is basically always "event" "origin" "message", then just make a function for that:

inline void report_error(int event, const std::string& origin, const std::string& message) {
  std::cout << "ERROR " << event 
            << ": "     << (origin ? origin : "?") 
            << ": "     << message 
            << std::endl;

Or use a MACRO like this:

#define ERROR_REPORT(A,B,C) "ERROR " << A << ": " << (B ? B : "?") << ": " << C

//and use it as:
std::cout << ERROR_REPORT(event,origin,fulltext) << std::endl;

Or use exception messages as Fbody said.

Or, just use printf, if you prefer, there's nothing really wrong with that. You should always consider the C++ options first because they are often better, but wherever the C style works fine, it's ok too (as long as it is within a small piece of code that is well encapsulated).

Edited by mike_2000_17: n/a


In this case it was an error report, but I write printf() in general MUCH faster then std::cout. Perhaps it's habit that will go away after a while.


Your eyes will also get used to the C++ version with time. For instance, I find the C++ version you posted more appealing to the eye. And your fingers will also get used to it, believe me.

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