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Thread: need help

  1. #1
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    Default need help

    i need a code that can print 6 random numbers. the first five numbers have to be from 51-100 and the sixth one has to be from 1-50, the numbers cannot repeat and they have to be sorted from greatest to least. i got the first two parts right but idk how to sort them after they've been shuffled. can someone please help me or give me some tips.

    import java.util.Random;
    import java.util.Collections;
     import java.util.ArrayList;
     public class Lottery {
     
       public static void main(String[] args) {
     
     
         ArrayList<Integer> numbers = new ArrayList<Integer>();
         for(int i = 51; i < 100; i++)
         {
         numbers.add(i);
       }
     
         Collections.shuffle(numbers);
         System.out.print("This week's lottery numbers are: ");
         for(int j =0; j < 5; j++)
         {
           System.out.print(numbers.get(j) + " ");
         }
      Random f = new Random();
    {
     
      int lastnum=f.nextInt(50) + 1;
     
      System.out.print("  "+lastnum);
    }
     
     
     
     
       }
     }

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: need help

    idk how to sort them
    Look at the Collections class. It has sort methods.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: need help

    if i use collection.sort(numbers) it just prints the same 5 numbers every time.
    51 52 53 54 55

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: need help

    What's in the collection before you sort it?
    If you don't understand my answer, don't ignore it, ask a question.

  5. #5
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    Default Re: need help

    before i used collection.sort i would get 5 random numbers from 51-100 unsorted and a 6th number from 1-50 which is always last and doesn't need to be sorted

    Output:
    This week's lottery numbers are: 95 55 74 65 99 43

    what i want the output to be:
    This week's lottery numbers are: 99 95 74 65 55 43

  6. #6
    Super Moderator Norm's Avatar
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    Default Re: need help

    Does the program print out the contents of the collection before it sorts it?
    What is printed?

    Can you post the current version of the program?
    If you don't understand my answer, don't ignore it, ask a question.

  7. #7
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    Default Re: need help

    I use JCreator LE V1.00. It does not show the contents of the collection. Below is exactly whats printed from the code above. the numbers are random everytime. I just need to find a way to put the numbers in order from greatest to least.

    This week's lottery numbers are: 60 74 75 87 71 22

  8. #8
    Super Moderator Norm's Avatar
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    Default Re: need help

    Print out the contents of the collection before you sort it. When you see that, you'll understand what the problem is.
    If you don't understand my answer, don't ignore it, ask a question.

  9. The Following User Says Thank You to Norm For This Useful Post:

    naz585 (December 16th, 2012)

  10. #9
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    Default Re: need help

    I saw what was wrong in the collection, i made two arraylists shuffled the first one and then added it to the second arraylist and then sorted the second one.
    ty norm