Compilare: user.cpp: In function ‘void euler(int)’: user.cpp:12:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[k].size();i++) ^ user.cpp:20:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[k].size();i++) ^ user.cpp:28:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[k].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:63:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<r.size()-1;i++) ^ user.cpp:42:39: 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:43:41: 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:45:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:48:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^