Compilare: user.cpp: In function ‘int main()’: user.cpp:10:7: warning: unused variable ‘cate’ [-Wunused-variable] int n,cate=0,v[10001],z=1,i; ^ user.cpp:7:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("g2.in","r",stdin); ^ user.cpp:8:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("g2.out","w",stdout); ^ user.cpp:12:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&n); ^