public HashMap<String, String> constructHashMap(){
        int num=255;
        HashMap<String,String> binaryDecimal = new HashMap<String, String>();
        binaryDecimal.put("00000000","0");
        StringBuilder remainders ;
        while(num!=0){
            remainders = new StringBuilder();
            int temp = num;
            while(temp!=0){
            remainders.append(temp%2);
            temp=temp/2;
            }
            binaryDecimal.put(eightBitZeros.substring(0,8-remainders.length())+remainders.reverse().toString(), String.valueOf(num));
            num--;
        }
        return binaryDecimal;
    }