/in/foo.c: In function 'Max':
/in/foo.c:28:9: error: 'i' undeclared (first use in this function)
  return i;
         ^
/in/foo.c:28:9: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:19:15: warning: variable 'imax' set but not used [-Wunused-but-set-variable]
  int max=a[0],imax=0;
               ^~~~
/in/foo.c:29:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^