Compilare: main.cpp: In member function 'void Permutations::permutations_main()': main.cpp:44:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("permutari.in", "r", stdin); ^ main.cpp:45:46: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("permutari.out", "w", stdout); ^ main.cpp:47:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^