Compilare: main.cpp: In function 'int main()': main.cpp:10:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("startrek.in", "r", stdin); ^ main.cpp:11:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("startrek.out", "w", stdout); ^ main.cpp:18:6: warning: 'nr' may be used uninitialized in this function [-Wmaybe-uninitialized] int nr; ^~