When writing a C program you might have the need to print the % percentage character using printf().

Perhaps you are working on a program that calculates percentages, which is kind of common when you’re just learning the language and you’re creating small programs.

How do you do so?

If you try to use it like this:

printf("%");

it will not work, and the compiler will give you a warning like

hello.c:9:14: warning: incomplete format specifier
      [-Wformat]
  printf("%");
          ^
1 warning generated.

and it is not printed.

To make it work, you need to write %%, like this:

printf("%%");