QueuesUsingStacks.java

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Scanner;
/*
 * Name: Janan Patel
 * Date: 10/18/2021
 * Course Number: Java 220 / Data Structures
 * Course Name: Java 220 / Data Structures
 * Problem Number: 5
 * Email: jkpatel2001@student.stcc.edu
 * Short Description of the Problem: Making a queue system for numbers.
 */

import java.util.Scanner;

public class QueuesUsingStacks {
	private final static String TITLE = "The Queue Program";
	private final static String CONTINUE_PROMPT = "Do this again? [y/N] ";

	private static Stack<Integer> stackNewestOnTop = new Stack<Integer>();
	private static Stack<Integer> stackOldestOnTop = new Stack<Integer>();

	// **********************************************
	// Put as many methods you need here
	public static void enqueue(int value) { // add item
		stackNewestOnTop.push(value);

	}

	public static int peek() { // Get oldest item
		shiftStacks();
		return stackOldestOnTop.peek();

	}

	public static boolean isEmpty(Stack<Integer> stack) { // returns if it's empty

		return stack.isEmpty();

	}

	private static void shiftStacks() { // shifts the stacks so we can get another stack with opposite information
		if (isEmpty(stackOldestOnTop)) {
			while (!isEmpty(stackNewestOnTop)) {
				stackOldestOnTop.push(stackNewestOnTop.pop());
			}
		}
	}

	public static int dequeue() { // Get oldest item and remove it
		shiftStacks();
		return stackOldestOnTop.pop();

	}

	public static void doProcess() throws Exception {

		try { // try catch block incase the user enters invalid data
			@SuppressWarnings("resource")
			Scanner sc1 = new Scanner(System.in);
			System.out.println("\nEnter a value from 0-9 in order to start the queue up: ");

			int number1 = sc1.nextInt();
			URL url = new URL("https://cs.stcc.edu/~silvestri/QueueQuery/QueueQuery" + number1 + ".txt");
			Scanner sc = new Scanner(url.openStream());
			int numberOfLines = sc.nextInt();

			while (numberOfLines > 0) {
				int queryNumber = sc.nextInt();
				if (queryNumber == 1) {
					int number = sc.nextInt();
					enqueue(number);
				}
				if (queryNumber == 2) {
					dequeue();
				}

				if (queryNumber == 3)
					System.out.println(peek());

				numberOfLines--;
			}
		} catch (Exception e) {
			System.out.println("The Values must be between 0 and 9");
		}

	}

	private static void reset() { // Resets the stacks for information doesn't stack
		while (!stackNewestOnTop.isEmpty()) {
			stackNewestOnTop.pop();
		}
		while (!stackOldestOnTop.isEmpty()) {
			stackOldestOnTop.pop();
		}
	}

	// **********************************************
	// Start your logic coding in the process method
	private static void process(Scanner input, String args[]) throws Exception {

		doProcess();
		reset();
	}

	// **********************************************
	// Do not change the doThisAgain method
	private static boolean doThisAgain(Scanner input, String prompt) {
		System.out.print(prompt);
		String doOver = input.nextLine();
		return doOver.trim().equalsIgnoreCase("Y");
	}

	// **********************************************
	// Do not change the main method
	public static void main(String args[]) throws Exception {
		System.out.println("Welcome to " + TITLE);
		Scanner input = new Scanner(System.in);
		do {
			process(input, args);
		} while (doThisAgain(input, CONTINUE_PROMPT));
		input.close();
		System.out.println("Thank you for using " + TITLE);
	}

}