Compilare: main.cpp: In function 'int main()': main.cpp:25:28: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::set<long long int>::size_type {aka long unsigned int}' [-Wformat=] printf("%d\n", s.size()); ^ main.cpp:8:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] { freopen("armonica.in", "r", stdin); ^ main.cpp:9:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("armonica.out", "w", stdout); ^ main.cpp:11:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &b); ^