/in/foo.cc: In function 'int main()':
/in/foo.cc:5:5: error: 'cin' was not declared in this scope
     cin>>a>>b;
     ^~~
/in/foo.cc:5:10: error: 'a' was not declared in this scope
     cin>>a>>b;
          ^
/in/foo.cc:5:13: error: 'b' was not declared in this scope
     cin>>a>>b;
             ^
/in/foo.cc:6:2: error: 'cout' was not declared in this scope
  cout<<a+b;
  ^~~~