# LAST issue! Random permutation array!

• May 4th, 2012, 11:41 PM
bankoscarpa
LAST issue! Random permutation array!
I have the array printing out just 0's. I am not sure what i have to input to make it output random digits. I want random digits 0-9, I am not sure what to do. This is the last program i need help on. Thank you for any help!

Code :

```/** This class prints 5 permutations of the numbers 1 through 10. */ public class PermutationPrinter { public static void main(String[] args) { PermutationGenerator gen = new PermutationGenerator(10);   for (int i = 1; i <= 5; i++) { for (int n : gen.nextPermutation()) System.out.print(" " + n); } } }```

Code :

```import java.util.Random; import java.util.*; /** This class generates permutations of a sequence of integers 1...length. */ public class PermutationGenerator { ArrayList<Integer> number = new ArrayList<Integer>(); int size;   /** Construct a PermutationGenerator object. @param length the length of the permutations generated by this generator. */ public PermutationGenerator(int length) { size = length; for (int i = 0; i <= length; i++){ number.add(i); } } /** Gets the next permutation. @return the array containing the next permutation */ public int[] nextPermutation() { int[] x = new int[size]; for( int i = 0; i<size; i++){ Random k = new Random(); int y = k.nextInt(number.size());   } return x; } }```
• May 5th, 2012, 02:15 AM
Parranoia
Re: LAST issue! Random permutation array!
In your nextPermutation() method, you are never adding the values from the for loop to your int array. So you are just creating a new array and passing on that empty array, which would contain all 0s
• May 5th, 2012, 02:25 AM
bankoscarpa
Re: LAST issue! Random permutation array!
That makes sense actually, but how would i go about doing that?
• May 5th, 2012, 06:28 AM
andreas90
Re: LAST issue! Random permutation array!
Quote:

Originally Posted by bankoscarpa
That makes sense actually, but how would i go about doing that?

You can just make an assignment statement after the creation of the random number (y). You should assign y to an index of your array.
• May 5th, 2012, 11:55 AM
Parranoia
Re: LAST issue! Random permutation array!
Something like
Code :

`x[i] = y;`