Compilare: user.cpp: In function ‘int main()’: user.cpp:6:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sushi.in","r",stdin); ^ user.cpp:7:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sushi.out","w",stdout); ^ user.cpp:29:19: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<i<<" "<<j<<" "<<2*val; ^ user.cpp:29:11: warning: ‘i’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<i<<" "<<j<<" "<<2*val; ^