shuffling

import java.util.Random;

public class Shuffler {

	public static Random r = new Random();

	public static void swap(int[] a, int i, int s) {
		int tmp = a[i];
		int tmp2 = a[s];
		a[i] = tmp2;
		a[s] = tmp;
	}

	public static void print(int[] a) {
		if(a==null) return;
		for(int i=0;i<a.length;i++) {
			System.out.print(a[i] + " ");
		}
		System.out.println();
	}

	public static void fisher_yates_shuffle(int [] a) {
		if (a.length>1) {
			int i = a.length - 1;
			while (i>0) {
				int s = r.nextInt(i+1);
				swap(a,i,s);
				i--;
			}
		}
	}

	public static void main(String[] args) {
		int [] a = {1,2,3,4,5};
		fisher_yates_shuffle(a);
		print(a);
	}

}