/in/foo.c: In function 'main':
/in/foo.c:7:2: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'for'
  for (i=0;i<n;i++)
  ^~~
/in/foo.c:8:16: error: 'a' undeclared (first use in this function)
   scanf("%d", &a[i]);
                ^
/in/foo.c:8:16: note: each undeclared identifier is reported only once for each function it appears in