public Vector<Object> subarray_as_Vector(int start, int end){
        if(end>=this.length)throw new IllegalArgumentException("end, " + end + ", is greater than the highest index, " + (this.length-1));
        Vector<Object> vec = new Vector<Object>(end-start+1);
        for(int i=start; i<=end; i++)vec.addElement(array.get(i));
        return vec;
    }