foo.cc: In function 'int main()':
foo.cc:6:9: error: 'cout' was not declared in this scope
    6 |         cout<<"输入年份:";
      |         ^~~~
foo.cc:7:9: error: 'cin' was not declared in this scope
    7 |         cin>>year;
      |         ^~~
foo.cc:8:30: error: expected primary-expression before '!=' token
    8 |         if(year%4==0 && year%!=0 || year%400==0)
      |                              ^~
foo.cc:9:36: error: 'endl' was not declared in this scope
    9 |                 cout<<year<<"yes"<<endl;
      |                                    ^~~~
foo.cc:11:35: error: 'endl' was not declared in this scope
   11 |                 cout<<year<<"no"<<endl;
      |                                   ^~~~