Compilare: user.cpp: In function ‘int main()’: user.cpp:6:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("avarcolaci.in", "r", stdin); ^ user.cpp:7:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("avarcolaci.out", "w", stdout); ^ user.cpp:28:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("avarcolaci.in" , "r", stdin); ^ user.cpp:16:13: warning: ‘last’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(a!=last && freq == 0) ^