Compilare: user.cpp: In function ‘void euler(int)’: user.cpp:24:9: warning: unused variable ‘last’ [-Wunused-variable] int last; ^ user.cpp: In function ‘int main()’: user.cpp:59:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < cycle.size () - 1; i++) ^ user.cpp:44:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "ciclueuler.in", "rt", stdin); ^ user.cpp:45:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "ciclueuler.out", "wt", stdout); ^