Styjun

The program needs to be able to enter people into a Queue and keep track of them. the user has 3 options "A" to enter a new person(int) into the queue, "N" to just let the queue be processed, and "Q" to quit the queue and to then display how many people are in the queue. I can't quite figure out how to loop and keep track.

package pkg3650queue;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner; // Import the Scanner class

public class Main 
/**
 * @param args the command line arguments
 */
public static void main(String[] args) 
 // TODO code application logic here
 Queue<Integer> line = new LinkedList<Integer>();
 Scanner input = new Scanner(System.in);
 Scanner addperson = new Scanner(System.in);

 String option;
do 
 System.out.println("Type A to add a person to the line (# of requests)n"
 + "Type N to do nothing and allow the line to be processedn"
 + "Type Q to quit the applicationn");
 option = input.nextLine();

 if(option.equalsIgnoreCase("A")) 
 System.out.println("Enter a number to add a person to the line: ");
 int addtoLine = addperson.nextInt();
 line.add(addtoLine);
 System.out.println(line);
 System.out.println("There are " + line.size() + " people in the queue");
 else if (option.equalsIgnoreCase("N")) 
 if(line.isEmpty())
 System.out.println("There are no elements in the line to be processed");
 System.exit(0); 
 
 else
 int requestsProccessed = line.remove();
 System.out.println(requestsProccessed);
 System.out.println(line);
 System.out.println("There are " + line.size() + " people in the queue");
 
 

 while (!option.equalsIgnoreCase("Q"));

System.out.println("Q was chosen. The number of ppl in this queue are " + line.size());

You mean how to loop the user input? You can use a do-while:

 String option;
 do 
 System.out.println("Type A to add a person to the line (# of requests)n"
 + "Type N to do nothing and allow the line to be processedn"
 + "Type Q to quit the applicationn");
 option = input.nextLine();

 if(option.equalsIgnoreCase("A")) 
 // do something
 else if (option.equalsIgnoreCase("N")) 
 // do something
 

 // notice we don't need an if for 'Q' here. This loop only determines how many
 // times we want to keep going. If it's 'Q', it'll exit the while loop, where
 // we then print the size of the list.

 while (!option.equalsIgnoreCase("Q"));

 System.out.println("Q was chosen. The number of ppl in this queue are " + line.size());

Note I didn't test this code, but it should get you going on the right track.

Also notice that we do not need a System.exit(0) in this case, as the program will just naturally end. Though there are exceptions, you normally do not want to use System.exit(0), and would rather find ways for code to 'finish itself'.