// CSE 143, Summer 2016
//
// A handy example of keeping track of web pages visited.

import java.util.*;

public class BackButton {
  public static void main(String[] args) {
    Stack<String> pages = new Stack<String>();

    visit("google.com", pages);
    visit("reddit.com", pages);

    System.out.println(pages);
    System.out.println();

    goBack(pages);
    System.out.println(pages);
    goBack(pages);
  }

  // visits page, and stores it in pages
  public static void visit(String page, Stack<String> pages) {
    System.out.println("Visiting " + page + "...");
    pages.push(page);
  }

  // goes back one page
  public static void goBack(Stack<String> pages) {
    String oldPage = pages.pop();
    System.out.println("Leaving " + oldPage + "...");
    if (!pages.isEmpty()) {
      String currentPage = pages.peek();

      System.out.println("Currently on " + currentPage);
    } else {
      System.out.println("No page!");
    }
  }
}