void test(){
    try{
        if (empty())
            throw empty_list();
            std::cout << p_que.front().owner << p_que.front().price << std::endl;
        }
    catch (std::exception &e){
        std::cout << "List is empty. " << std::endl << "Error message: " << e.what() << std::endl << std::endl;
    }
}


#pragma once
#include <exception>
#include <iostream>


class empty_list:public std::exception
{
public:
    const char* what() const throw(){
        return "You cannot print the list because there's nothing in it.";
    }
};