Question

I need help with this coding.

A. Create ArrayIntStack.java (one that's REALLY O(constant), totally!!!)

B. Create the Javadoc web page (separate Assignment #15b).

A. Create your own Stack Class, call it ArrayIntStack.java and write the standard four public Stack methods as listed below (this is the easy part of the assignment). Use at least one private helper method, maybe to ensure capacity of the array. All methods in your ArrayIntStack must have O(constant) run-time. Your ArrayIntStack extends no other Classes from the Java API. You must provide a default constructor.

1. boolean empty(); Tests if this stack is empty (watch spelling here, as I will)
2. int peek(); Looks at the object at the top of this stack without removing it from the stack.
3. int pop(); Removes the object at the top of this stack and returns that object as the value of this function.
4. int push(int item); Pushes an item onto the top of this stack, return what was pushed.

Additional methods, code, etc... will also need to be provided, so the client can use an iterator:

5. public class IntStackIterator { // similar to what the BJP authors show, but without a remove() implemented
6. public IntStackIterator iterator() method so the client can browse through the data with .next() etc... Start the iterator at the top of the stack!!!

You must throw an "appropriate" Exception (e.g. EmptyStackException) for illegal peek, pop, etc... operations. Regarding size, let's say this remains O(constant) while the Stack size is less than 20 elements, beyond that the push(int) would need to throw a Stack Overflow.

Answer 1

Here is the implementation of stack using linked list in java.

class arrayIntStack

{

    protected int arr[];

    protected int top, size, len;

    /*  Constructor for arrayStack */

    public arrayStack(int n)

    {

        size = n;

        len = 0;

        arr = new int[size];

        top = -1;

    }

    /*  Function to check if stack is empty */

    public boolean isEmpty()

    {

        return top == -1;

    }

    /*  Function to check if stack is full */

    public boolean isFull()

    {

        return top == size -1 ;        

    }

    /*  Function to get the size of the stack */

    public int getSize()

    {

        return len ;

    }

    /*  Function to check the top element of the stack */

    public int peek()

    {

        if( isEmpty() )

            throw new NoSuchElementException("Underflow Exception");

        return arr[top];

    }

    /*  Function to add an element to the stack */

    public void push(int i)

    {

        if(top + 1 >= size)

            throw new IndexOutOfBoundsException("Overflow Exception");

        if(top + 1 < size )

            arr[++top] = i;

        len++ ;

    }

    /*  Function to delete an element from the stack */

    public int pop()

    {

        if( isEmpty() )

            throw new NoSuchElementException("Underflow Exception");

        len-- ;

        return arr[top--]; 

    }    

    /*  Function to display the status of the stack */

    public void display()

    {

        System.out.print("\nStack = ");

        if (len == 0)

        {

            System.out.print("Empty\n");

            return ;

        }

        for (int i = top; i >= 0; i--)

            System.out.print(arr[i]+" ");

        System.out.println();

    }    

}