package examples.stack1;

/**
 * Author: W. M. Farmer <BR>
 * Revised: February 11, 2007 <BR>
 * <BR>
 * Description: Implements a stack as an array.
 */
public class Stack {

    private static final int MAX = 1000;

    private static int[] stack_ = new int[MAX];
    private static int height_ = 0;

    /**
     * Selector that gets the top element of the stack.
     * 
     * @return top element of the stack
     */
    public static int top() {
	if (height_ != 0)
	    return stack_[height_ - 1];
	else {
	    System.out.println("Error in top(): Stack is empty.");
	    return 0;
	}
    }

    /**
     * Selector that gets the height of the stack.
     * 
     * @return height of the stack
     */
    public static int height() {
	return height_;
    }

    /**
     * Mutator that pushs an element onto the stack.
     * 
     * @param element value to be pushed onto the stack
     */
    public static void push(int element) {
	if (height_ != MAX) {
	    stack_[height_] = element;
	    height_ = height_ + 1;
	}
	else 
	    System.out.println("Error in push(" +
			       String.valueOf(element) +
			       "): Stack is empty.");
    }

    /**
     * Mutator that pops the stack.
     */
    public static void pop() {
	if (height_ != 0)
	    height_ = height_ - 1;
	else 
	    System.out.println("Error in pop(): Stack is empty.");
    }

    /**
     * Prints the contents of the stack.
     */
    public static void print() {
	String s;
	s = "Stack contents: [";
	for (int i = 0; i < height_; i++) {
	    if (i + 1 == height_)
		s = s + String.valueOf(stack_[i]);
	    else
		s = s + String.valueOf(stack_[i]) + ",";
	}
	s = s + "].";
	System.out.println(s);
    }

}