Compilare: user.cpp: In function ‘int main()’: user.cpp:31:9: warning: unused variable ‘i’ [-Wunused-variable] int i,j,x; ^ user.cpp:31:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,x; ^ user.cpp:29:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.in","r",stdin); ^ user.cpp:30:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.out","w",stdout); ^ user.cpp:32:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^