Question

This question pertains to ANSI C. I think that it should be a simple answer…so which of these methods is the fastest? It doesn’t really have anything to do with my current projects but it just came to mind one day and I didn’t see the answer right away on the web…

Answer 1

printf is by far preferable, by many orders of magnitude and in every sense. It is a library function that’s part of the C standard, and it makes your own program print the desired output. system on the other hand launches a new, separate process (something that takes a comparable eternity), and you still have to hope that your shell actually provides an echo command that does the same thing.

The only thing worse than calling system on echo would be to call system to invoke a compiler that compiles another program that contains printf and run that, I guess…

Don’t use system.