Compilare: main.cpp: In function 'int main()': main.cpp:22:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s.size() == N) return 0; ~~~~~~~~~^~~~ main.cpp:7:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("password2.in", "r", stdin); ^ main.cpp:8:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("password2.out", "w", stdout); ^