Compilare: user.cpp: In function ‘int main()’: user.cpp:19:9: warning: unused variable ‘u’ [-Wunused-variable] int u=0; ^ user.cpp:7:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("minecraft.in","r",stdin); ^ user.cpp:8:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("minecraft.out","w",stdout); ^ user.cpp:10:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:13:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^