Prev

void  Prev(
   CObject*  object      // указатель на предыдущий элемент списка
   )

//--- example for CObject::Prev(CObject*)
#include <Object.mqh>
//---
void OnStart()
  {
   CObject *object_first,*object_second;
   //---
   object_first=new CObject;
   if(object_first==NULL)
     {
      printf("Object create error");
      return;
     }
   object_second=new CObject;
   if(object_second==NULL)
     {
      printf("Object create error");
      delete object_first;
      return;
     }
   //--- set interconnect
   object_first.Next(object_second);
   object_second.Prev(object_first);
   //--- use objects
   //--- ...
   //--- delete objects
   delete object_first;
   delete object_second;
  }