text: #include <iostream>
  #include "queue_by_linked_list_template.h"
  
  
  int main() {
      Queue<int> zx;
      zx.enqueue(5);
      zx.enqueue(4);
      std::cout << zx;
      std::cout << zx.len() << std::endl;
      auto i = zx.dequeue();
      std::cout << zx;
      std::cout << i << std::endl;
      std::cout << zx.len();
  }
  