Permutation.java

public class Permut {
	public void print(int[] ar){
		for(int a : ar){
			System.out.print(a + " ");
		}
		System.out.println();
	}
	
	public void swap(int[] ar, int a, int b){
		int temp = ar[b];
		ar[b] = ar[a];
		ar[a] = temp;
	}
	
	
	public void f(int [] ar, int i)
	{
	    int j = i;
	    for (j = i; j < ar.length; j++) {
	        swap(ar, i, j);
	        f(ar, i+1);
	        swap(ar, i, j);
	    }
	    if (ar.length-1 == i) {
	        print(ar);
	        return;
	    }
	}
	
	void permute(int[] arr, int k){
        for(int i = k; i < arr.length; i++){
            swap(arr, i, k);
            permute(arr, k+1);
            swap(arr, k, i);
        }
        if (k == arr.length -1){
            System.out.println(java.util.Arrays.toString(arr));
        }
    }
	
	public static void main(String[] args) {
		Permut p = new Permut();
		int[] ar = {1,2,3}; 
		//p.f(ar, 0, ar.length-1);
		p.f(ar,0);
	}
	 
}