Click on queue.h to get source.
// File Circlist/MultInher/queue.h
#include "circlist.h"

class queue : public virtual circlist {
public:
      queue(void)       {}
 void enterq(int x);
 int  leaveq(void);
};

void queue::enterq(int x) { enter(x); }

int  queue::leaveq(void)      { return pop(); }