/in/foo.c: In function 'main':
/in/foo.c:8:27: error: 'i' undeclared (first use in this function)
  for(int x=xmin;x<=xmax;++i)
                           ^
/in/foo.c:8:27: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:13:10: error: expected ';' before ':' token
  return 0: 
          ^