foo.cc:11:2: error: expected initializer before 'int'
  int n, res = 0; scanf("%d", &n);
  ^~~
foo.cc:11:23: error: expected constructor, destructor, or type conversion before '(' token
  int n, res = 0; scanf("%d", &n);
                       ^
foo.cc:12:7: error: expected constructor, destructor, or type conversion before '(' token
  scanf("%s", a);
       ^
foo.cc:13:2: error: expected unqualified-id before 'for'
  for ( auto i : a )
  ^~~
foo.cc:15:8: error: expected constructor, destructor, or type conversion before '(' token
  printf("%d", res);
        ^
foo.cc:16:1: error: expected declaration before '}' token
 }
 ^

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