Compilare: user.cpp: In function ‘int main()’: user.cpp:33:32: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘std::set<std::pair<int, int> >::size_type {aka long unsigned int}’ [-Wformat=] printf("%d\n", s.size()); ^ user.cpp:12:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:15:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &ship.first, &ship.second); ^