Compilare: user.cpp: In function ‘int main()’: user.cpp:9:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("imagine.in" , "r", stdin ); ^ user.cpp:10:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("imagine.out", "w", stdout); ^ user.cpp:13:35: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(str, 1e7 + 1, stdin); ^