Compilare: user.cpp: In function ‘void euler(int)’: user.cpp:14:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[w].size (); i++) ^ user.cpp: In function ‘int main()’: user.cpp:38:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ciclu.size () - 1; i++) ^ user.cpp:28:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "euler.in", "rt", stdin); ^ user.cpp:29:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "euler.out", "wt", stdout); ^