View Compilation Error

0_0_39670114_19555.cpp:7:14: error: expected unqualified-id before ')' token
    7 | struct Rule1() (const int & a, const int & b) const {
      |              ^
0_0_39670114_19555.cpp: In function 'int main()':
0_0_39670114_19555.cpp:15:33: error: expected primary-expression before ')' token
   15 |                 sort(a,a+n,Rule1);
      |                                 ^