Compilare: user.cpp: In function ‘int main()’: user.cpp:8:15: warning: unused variable ‘nr’ [-Wunused-variable] int n,i,x,nr=0,ok,u; ^ user.cpp:6:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen("loto2.in","r",stdin); ^ user.cpp:7:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("loto2.out","w",stdout); ^ user.cpp:25:8: warning: ‘u’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<u; ^