class Stuff {
    // instance vars:
       private int[] x = new int[3]; // create int array with 3 defaults
       private int[] y;              // declare int array
       private int[] z = {1,2,3,4} ; // create array with ints 1,2,3,4

    // constructor:
       public Stuff(int n) {
   	    y = new int[3]; // create $y$ array with size $n$
	    fillY(); // fill $y$ with random values
       }

    // Fill $y$ with random values 0 or 1:
       private  void  fillY() {
	   for (int i = 0 ; i < y.length ; i++ )
	       y[i] = (int)(Math.random()*2) ;
       }

    // Choose array and return it:
       public int[] getArray(int choice) {
	   int[] a;
	   switch(choice) {
	   case 1:  a = x; break;
	   case 2:  a = y; break;
	   case 3:  a = z; break;
	   default: a = new int[] {} ; break; // return empty array
	   }
	   return a;
       }
} // class Stuff

public class classWithArrays {
    public static void main(String[] args) {
	Stuff s = new Stuff(5);
	print(s.getArray(1));
	print(s.getArray(2));
	print(s.getArray(3));
	print(s.getArray(10));
    }
    public static void print(int[] v) {
	for (int i = 0 ; i<v.length ; i++ )
	    System.out.print(v[i] + " ");
	System.out.println();
    }
} // class classWithArrays