foo.c: In function ‘main’:
foo.c:7:18: warning: unknown conversion type character ‘\x0a’ in format [-Wformat=]
    7 |         printf("%\n", a + b);
      |                  ^~
foo.c:7:16: warning: too many arguments for format [-Wformat-extra-args]
    7 |         printf("%\n", a + b);
      |                ^~~~~