/in/foo.cc: In function 'int main()':
/in/foo.cc:5:9: error: 'cin' was not declared in this scope
         cin>>x;
         ^~~
/in/foo.cc:6:14: error: 'sqrt' was not declared in this scope
  int n=sqrt(x);
              ^
/in/foo.cc:11:4: error: 'cout' was not declared in this scope
    cout<<x1+x/x1<<endl; 
    ^~~~
/in/foo.cc:11:19: error: 'endl' was not declared in this scope
    cout<<x1+x/x1<<endl; 
                   ^~~~