What is the meaning of f in printf? [closed]

Question

What is the meaning of "f" in C's printf?

Answer 1

The f in printf stands for formatted, its used for printing with formatted output.

Answer 2

As others have noted, the trailing f indicates formatted output (or formatted input for functions in the scanf family).

However, I'll add that the distinction matters because it's important for callers to know that the string is expected to have format-specifier semantics. For example, do not do this:

char* s = get_some_user_input();
printf(s); // WRONG.  Instead use: printf("%s", s) or fputs(stdout, s)

If s happens to contain % characters, printing it directly with printf can cause it to access non-existent arguments, leading to undefined behavior (and this is a cause for some security vulnerabilities). Keep this naming convention in mind if you ever define your own printf-like variadic functions.