foo.cc: In function 'int main()':
foo.cc:6:2: error: 'cin' was not declared in this scope
  cin >> a >> b;
  ^~~
foo.cc:6:2: note: suggested alternative: 'main'
  cin >> a >> b;
  ^~~
  main
foo.cc:7:2: error: 'cout' was not declared in this scope
  cout << a + b;
  ^~~~

正在同步测试数据，请稍后
[Hydro](https://hydro.ac)提供评测服务