Why won't my program continue on once I enter as the itemName?

Question

I can't figure out why my program won't continue past the while loop once I enter the string "end" as one of the items. I tried putting println statements after the while loop and they didn't print after I typed "end". I also tried putting a print statement at the end of the while loop and it did not print once I typed "end", so it isn't running the while loop after I type "end", but it also isn't running anything after it. Any ideas? Here's the code:

package a1;

import java.util.Scanner;

public class A1Adept {
    public static void main(String[] args) {
           Scanner s = new Scanner(System.in);

           process(s);
    }

    public static void process(Scanner s) {

           int[] numbers = new int[10];
           double[] cost = new double[10];
           String itemName = "";
           int categoryNumb;
           int quantities;
           double costs;

           System.out.println("Please enter the names of the items, their category, their quantity, and their cost.");

           while(!itemName.equals("end")){             

               itemName = s.next();
               categoryNumb = s.nextInt();
               quantities = s.nextInt();
               costs = s.nextDouble();

               numbers[categoryNumb] += quantities;
               cost[categoryNumb] += (costs*quantities);

               }
           System.out.println("win");
           int qMax = 0;
           int qMin = 0;
           int cLarge = 0;
           int cLeast = 0;
           int max = 0;
           int min = 100;
           double large = 0;
           double least = 100;

           for (int i = 0; i < 10; i++){
               if (numbers[i] >= max)
               {
                   max = numbers[i];
                   qMax = i;
               }
               if (numbers[i] <= min){
                   min = numbers[i];
                   qMin = i;
               }
               if (cost[i] >= large){
                   large = cost[i];
                   cLarge = i;                
               }
               if (cost[i] <= least){
                   least = cost[i];
                   cLeast = i;
               }
           }

           System.out.println("Category with the most items:"+qMax);
           System.out.println("Category with the least items:"+qMin);
           System.out.println("Category with the largest cost:"+cLarge);
           System.out.println("Category with the least cost:"+cLeast);


           }

    }

Answer 1

It will stop if you write "end" followed by an int, another int and a double.

This is because you are first checking for "end", then asking for the 4 inputs.

The while(condition) is evaluated at the beginning of every loop.

So your program goes like this :

1. Check if itemName equals "end"
2. Ask itemName
3. Ask categoryNumb
4. Ask quantities
5. Ask costs
6. Do your stuff
7. Go back to 1

If you want to exit as soon as the user types "end" change it to :

while (true) {  // Creates an "endless" loop, will we exit from it later
  itemName = s.next();
  if (itemName.equals("end")) break; // If the user typed "end" exit the loop
  // Go on with the rest of the loop