foo.c:4:9: error: macro names must be identifiers
foo.c:5:9: error: macro names must be identifiers
foo.c: In function 'main':
foo.c:10:5: error: 'cin' undeclared (first use in this function)
foo.c:10:5: note: each undeclared identifier is reported only once for each function it appears in
foo.c:11:5: error: 'cout' undeclared (first use in this function)