Compilare: user.cpp: In function ‘int main()’: user.cpp:27:8: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k,tur=0,sum=0; ^ user.cpp:27:10: warning: unused variable ‘k’ [-Wunused-variable] int i,j,k,tur=0,sum=0; ^ user.cpp:29:23: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(IN,"r",stdin); ^ user.cpp:30:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:35:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] sum+=a[i].x; ^ user.cpp:40:25: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(OUT,"w",stdout); ^