class diagram

I am drawing a class diagram of a rational number calculator program that I've created and I have a question about the relationship between some of the classes - the program has been completed so the class diagram has to reflect the finished version, (even though you may not agree with the design I have a question about the UML notation I should use)
the question is:
if the top level class (e.g. I named it Calculator) has an instance of a Stacks class (a class written that uses a Stack interface and the pop, peek methods are written to push nodes (an inner private class in the Stacks class ) and and then this stack instance (which was instantiated in Calculator class )  is placed as an input parameter to another class's method for e.g. an object of CalcIOConsole class is in the Calculator class and invokes a method to display the stack, is there an association between the CalcIOConsole class and the Stacks class (i.e should a line be drawn between these two classes, or only from the Calculator class to the Stacks class?)
At the moment I have a weak aggregration from the Calculator class to the StacksInterface class. (the Stacks class created implements the StacksInt interface and the object is instantiated as a StackInt object with new Stacks<Rational>();
the rational class is instantiated in the Calculator class as well,  (the numbers are stored as Rational objects from a Rational class which has a nominator/demoniator).  if a rational object is instantiated or returned by a method in the CalcIOConsole class  does it have a direct association with the rational class?
At the moment I have  :
CalcIOConsole--------->>CalcIOInterface<-----------------Calulator_______>Rational

>> means implements
<----- means depends on
______> means association