Compilare: main.cpp:1:2: warning: #import is a deprecated GCC extension [-Wdeprecated] #import <iostream> ^~~~~~ main.cpp: In function 'int main()': main.cpp:2:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int main(){freopen("fenrir.in","r",stdin);freopen("fenrir.out","w",stdout);std::cout<<"99\n";for(int i=9;++i<21;)for(int j=0;++j<10;)std::cout<<i<<" "<<j<<"\n";} ^ main.cpp:2:75: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int main(){freopen("fenrir.in","r",stdin);freopen("fenrir.out","w",stdout);std::cout<<"99\n";for(int i=9;++i<21;)for(int j=0;++j<10;)std::cout<<i<<" "<<j<<"\n";} ^