foo.cc: In function ‘int main()’:
foo.cc:7:25: error: ‘endl；’ was not declared in this scope
    7 |         cout<<"1"<<"1"<<endl；
      |                         ^~~~~~
foo.cc:5:14: warning: unused variable ‘n’ [-Wunused-variable]
    5 |         bool n;
      |              ^
foo.cc:6:14: warning: unused variable ‘v’ [-Wunused-variable]
    6 |         char v;
      |              ^