package example1;

// Note: This class implements a stack of Strings only.
public class MyStack {

	// The maximum possible size of the stack.
	public static final int MaxSize = 100;
	
	// The array index of the last active element
	// in the stack. A value of -1 means the stack
	// is currently empty.
	private static int top = -1;
	
	// The stack elements, stored in an array.
	private static String[] store = new String[MaxSize];

	// Add a new element at the top of the stack
	// (if there’s space left).
	public static void push(String newVal) {
		if (top < MaxSize - 1) {
			top++;
			store[top] = newVal;
		} else {
			System.out.println("Sorry, stack full.");
		}
	}
	
	// Remove the top element of the stack and return
	// it; check that the stack has elements in it!
	public static String pop() {
		String ans = "";
		if (top >= 0) {
			ans = store[top];
			top--;
		} else {
			System.out.println("Sorry, stack empty.");
		}
		return ans;
	}

	// Return the number of elements that are 
	// currently in the stack.
	public static int size() {
		return top + 1;
	}

	
}