/in/foo.cc: In function 'int main()':
/in/foo.cc:10:4: error: expected primary-expression before ']' token
  a[] ,da[] .....
    ^
/in/foo.cc:10:10: error: expected primary-expression before ']' token
  a[] ,da[] .....
          ^
/in/foo.cc:11:14: error: 'i' was not declared in this scope
  for(int i=2;i<=n;i++)
              ^