foo.cc: In function ‘int main()’:
foo.cc:19:5: warning: unused variable ‘t’ [-Wunused-variable]
   19 | int t=q.top();
      |     ^
foo.cc:21:9: error: ‘t’ was not declared in this scope
   21 | q2.push(t);
      |         ^
foo.cc: At global scope:
foo.cc:33:1: error: expected unqualified-id before ‘return’
   33 | return 0;
      | ^~~~~~
foo.cc:34:1: error: expected declaration before ‘}’ token
   34 | }
      | ^