// A Stack that contains Person objects.

public class Stack
{
    final int SIZE = 200;
    Person[ ] array;
    int top;

    public Stack( )
    {
        array = new Person[SIZE];
        top = -1;
    }

    public boolean isEmpty( )
    {
        return top == -1;
    }

    public boolean isFull( )
    {
        return top == SIZE - 1;
    } 

    public Person getTop( )
    {
        if (!isEmpty( ))
            return array[top];
        else
            return null;
    }

    public void push(Person p)
    {
        if (!isFull( ))
            array[++top] = p;
    }

    public void pop( )
    {
        if (!isEmpty( ))
            top--;        
    }

    public String toString( )
    {
        String output = "Contents of Stack object:\r\n";
        for(int i = top; i >= 0; i--)
        {
            output += i + ": ";
            output += array[i].toString( );
            output += "\r\n";
        }
        return output;
    }
}