1struct R 2{ 3 long long r1, r2; 4 void copy (R const &r) { r1 = r.r1; r2 = r.r2; } 5 R (); 6 explicit R (int, int); 7 R (R const &r) { copy (r); } 8 static int compare (R const &, R const &); 9}; 10