public String toIPV4(){
        int i=3;
        String result="";
        int num=getNum();
        while(true){
            int temp = num%256;
            if(i<0)
                break;
            if(i==3)
                result = String.valueOf(num%256);
            else
                result = String.valueOf(num%256)+DELIMITER+result;
            num/=256;
            i--;
        }
        return result;
    }