/in/foo.c: In function 'main':
/in/foo.c:5:11: error: 'Rd' undeclared (first use in this function)
    printf(Rd-defender);
           ^~
/in/foo.c:5:11: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:5:14: error: 'defender' undeclared (first use in this function)
    printf(Rd-defender);
              ^~~~~~~~