How to escape the % (percent) sign in C's printf?

Question

How do you escape the % sign when using printf in C?

printf(\"hello\\%\"); /* not like this */

Answer 1

Nitpick:
You don't really escape the % in the string that specifies the format for the printf() (and scanf()) family of functions.

The %, in the printf() (and scanf()) family of functions, starts a conversion specification. One of the rules for conversion specification states that a % as a conversion specifier (immediately following the % that started the conversion specification) causes a '%' character to be written with no argument converted.

The string really has 2 '%' characters inside (as opposed to escaping characters: "a\bc" is a string with 3 non null characters; "a%%b" is a string with 4 non null characters).