Compilare: user.cpp: In function ‘int main()’: user.cpp:36:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k=0;k<factor[v[j]].size();k++) { ^ user.cpp:11:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pairs.in","r",stdin); ^ user.cpp:12:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pairs.out","w",stdout); ^ user.cpp:13:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); fr[1]=1; ^ user.cpp:23:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); j=1; xx=x; nr=0; ^