/in/foo.cc: In function 'int main()':
/in/foo.cc:79:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<student>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |   for (int x = 0; x < v.size()-1; x++) {
      |                   ~~^~~~~~~~~~~~
/in/foo.cc: In function 'bool mysort(student, student)':
/in/foo.cc:22:1: warning: control reaches end of non-void function [-Wreturn-type]
   22 | }
      | ^