text: #ifndef QUEUE_SLL
  #define QUEUE_SLL
  #include<singly_ll.h>
  
  template<class t>
  class QUEUE {
  	private:	
  		sll<t> queue_list;
  
  	public:
  		QUEUE();
  		bool isempty(bool err_mssg = false);
  		void insert(t val);
  		t remove();
  		void display();
  };
  
  #include<queue_sll_func_def.h>
  
  #endif