ArrayList lottery game - excess array lists

Question

I have been tinkering with this program for a while, but I still do not know what is wrong. My problem is that if I want to get more than 1 ticket it gives me more array lists than expected. I cannot find a pattern as if I enter 2, I get 3, and if I enter 3, I get 6, and if I enter 4, I get back 10.

Input: Amount for how many tickets I want.

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class ArrayListLottery {
   public static void main(String[] args) {
      int range = 49, amount = -1, number = 0, choice = -1;
      // ArrayList<Integer> tickets = new ArrayList<Integer>();
      ArrayList<ArrayList<Integer>> games = new ArrayList<ArrayList<Integer>>();
      do {
         System.out.println("Enter amount of lottery tickets you want");
         Scanner in = new Scanner(System.in);
         if (amount < 0) {
            amount = in.nextInt();
         }
         while (amount != 0) {
            System.out.println("Entered while block");  
            for (int i = 0; i < amount; i++) {
               // Create an arraylist for how
               // many tickets i want
               ArrayList<Integer> tickets = new ArrayList<Integer>();
               games.add(tickets);
               for (int k = 0; k < 6; k++) { // Limit the size of a ticket to
                                             // 6
                  if (tickets.size() < 6) {
                     number = (int) (range * Math.random()) + 1;
                     tickets.add(number);
                     Collections.sort(tickets);
                  } else { 
                     break;
                  }
               }// limit for loop to 6 end
            }// arraylist creator end
            amount--;
            System.out.println("Amount is " + amount);
         }//while loop end

         for (List<Integer> i : games) { //print out each ticket
            for (Integer n : i) {
               System.out.print(n + " ");
            }
            System.out.println();
         } //print out for-loop end

         games.clear();

         System.out.println("Type 0 to exit, otherwise pick any other number ");
         choice = in.nextInt();
         amount = choice;
      } while (amount != 0);
      System.out.println("Good luck!");
   }
}

Answer 1

You can put

amount--;

in the for loop which generate the arraylist.

Like this:

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class ArrayListLottery {
   public static void main(String[] args) {
      int range = 49, amount = -1, number = 0, choice = -1;
      // ArrayList<Integer> tickets = new ArrayList<Integer>();
      ArrayList<ArrayList<Integer>> games = new ArrayList<ArrayList<Integer>>();
      do {
         System.out.println("Enter amount of lottery tickets you want");
         Scanner in = new Scanner(System.in);
         if (amount < 0) {
            amount = in.nextInt();
         }
         while (amount != 0) {
            System.out.println("Entered while block");  
            for (int i = 0; i < amount; i++) {
               // Create an arraylist for how
               // many tickets i want
               ArrayList<Integer> tickets = new ArrayList<Integer>();
               games.add(tickets);
               for (int k = 0; k < 6; k++) { // Limit the size of a ticket to
                                             // 6
                  if (tickets.size() < 6) {
                     number = (int) (range * Math.random()) + 1;
                     tickets.add(number);
                     Collections.sort(tickets);
                  } else { 
                     break;
                  }
               }// limit for loop to 6 end
               amount--;
            }// arraylist creator end
            System.out.println("Amount is " + amount);
         }//while loop end

         for (List<Integer> i : games) { //print out each ticket
            for (Integer n : i) {
               System.out.print(n + " ");
            }
            System.out.println();
         } //print out for-loop end

         games.clear();

         System.out.println("Type 0 to exit, otherwise pick any other number ");
         choice = in.nextInt();
         amount = choice;
      } while (amount != 0);
      System.out.println("Good luck!");
   }
}

Besides that, you can add a breakpoint to step over your program line by line which may make you find the bug quickly.

Answer 2

Fibonacci number of amount will be your size of games list.

It is happening because you have applied while as well as for loop for amount.

Replace your while loop with if statement.