/in/foo.cc: In function 'int main()':
/in/foo.cc:7:8: error: 'cin' was not declared in this scope
        cin>>po[i];
        ^~~
/in/foo.cc:7:8: note: suggested alternative: 'main'
        cin>>po[i];
        ^~~
        main
/in/foo.cc:16:13: error: 'cout' was not declared in this scope
             cout<<s;
             ^~~~