Compilare: user.cpp: In function ‘int main()’: user.cpp:61:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < ans.size() - 1; ++i) ^ user.cpp:40:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.in","r",stdin); ^ user.cpp:41:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.out","w",stdout); ^ user.cpp:43:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:47:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘void euler(int)’: user.cpp:30:20: warning: ‘link’ may be used uninitialized in this function [-Wmaybe-uninitialized] euler(link); ^