toString

[Dustin Schreader]

I'm trying to make a toString to display my stack but i'm getting incompatible types. its the method starting on 106.

public class LinkedStackClass<T> implements StackADT<T>
{
        //Definition of the node
    protected class StackNode<T>
    {
        public T info;
        public StackNode<T> link;

          
			 
			  //Default constructor
           //Postcondition: info = null; link = null;
        public StackNode()
        {
            info = null;
            link = null;
        }

           //Constructor with parameters
           //Sets info point to the object elem points to
           //and link is set to point to the object ptr
           //points to.
           //Postcondition:  info = elem; link = ptr
        public StackNode(T elem, StackNode<T> ptr)
        {
            info = elem;
            link = ptr;
        }

           //Method to return the info as a string.
           //Postcondition: info as a String object is
           //               returned.
        public String toString()
        {
            return info.toString();
        }
    }

        //Instance variable
    protected StackNode<T> stackTop;  //reference variable to the
                                    //top element of the stack

        //Default constructor
        //Postcondition: stackTop = null
    public LinkedStackClass()
    {
        stackTop = null;
    }//end constructor

        //Method to initialize the stack to an empty state.
        //Postcondition: stackTop = null
    public void initializeStack()
    {
        stackTop = null;
    }//end initializeStack

        //Method to determine whether the stack is empty.
        //Postcondition: Returns true if the stack is empty;
        //               otherwise, returns false.
    public boolean isEmptyStack()
    {
        return (stackTop == null);
    }

        //Method to determine whether the stack is full.
        //Postcondition: Returns true if the stack is full;
        //               otherwise, returns false.
    public boolean isFullStack()
    {
        return false;
    }

        //Method to add newItem to the stack.
        //Postcondition: The stack is changed and newItem
        //               is added to the top of stack.
    public void push(T newElement)
    {
        StackNode<T> newNode; //reference variable to create
                              //the new node

        newNode = new
                  StackNode<T>(newElement, stackTop); //create
                                          //newNode and insert
                                          //before stackTop

        stackTop = newNode; //set stackTop to point to
                            //the top element
    } //end push


        //Method to return a refernece to the top element of
        //the stack.
        //Precondition: The stack exists and is not empty.
        //Postcondition: If the stack is empty, the method throws
        //               StackUnderflowException; otherwise, a
        //               reference to the top element of the stack
        //               is returned.
    public T peek() throws StackUnderflowException
    {
        if (stackTop == null)
            throw new StackUnderflowException();

        return stackTop.info;
    }//end top
	 
	 public String toString()
	 {
	 	return stackTop.toString;  //<==== working on this toString
	 }


        //Method to remove the top element of the stack.
        //Precondition: The stack exists and is not empty.
        //Postcondition: The stack is changed and the top
        //               element is removed from the stack.
        //               If the stack is empty, the method throws
        //               StackUnderflowException
    public void pop() throws StackUnderflowException
    {
        if (stackTop == null)
            throw new StackUnderflowException();

        stackTop = stackTop.link;  //advance stackTop to the
                                   //next node
    }//end pop
}

[fred rosenberger]

should line 108 be

return stackTop.toString();

(missing the parens)

[Dustin Schreader]

I sure do feel silly now thank you

[Dustin Schreader]

although When it prints out in gui it only prints out 1 item of the stack what I would like it to do is keep printing out the entire stack such as
4
3
2
n
t
So you can see every element in the stack, this is what i'm using in my gui to print it out at the moment.

outputStackTF.setText(myStack.toString());

[fred rosenberger]

I've just barely skimmed your code, so i may not be correct. But it looks to me like in your public String toString() method, you are only calling the toString() method on the top element...therefore, it only prints what is in the top element.

What you would need to do is write some code that reads each element in the stack and calls IT'S toString() method.