CODEWITHSUNDEEP
javabinarybigintegerrandomaccessfile
George
George

Reputation: 21

Java BigInteger with very large binary numbers

i have 2 very large binary numbers (144 digits). I want to write them in different RandomAccessFiles and then read the files to memory and check to see which number is bigger. What i did so far:

1. I created a BigInteger:

BigInteger big = new BigInteger("01110101010010101010111100010101010101010101010110101010101010101010010101010101010101010101010101111010010101010",2);

2. I get the longValue:

big.longValue();

3.. I write the long to a randomaccessfile,read the files,compare the longs etc...

But if the binary is longer than the 'Long.maxvalue' what i did is wrong, correct?

So does anyone have any suggestions?

Can i handle large binary numbers otherwise?

Upvotes: 2

Views: 1810

Answers (3)

Vincent Cantin
Vincent Cantin

Reputation: 17262

Obviously, your number is too large for a long.

I recommend you to export your BigInteger as a byte array using BigInteger.getByteArray(), and then you can save it to a file (that's what we do in cryptography).

Also, the byte array can be converted back to a BigInteger using its contructor.

Upvotes: 0

Madhujith
Madhujith

Reputation: 157

  1. eliminate initial zeros

  2. Convert these numbers to Strings

  3. if(String1.length !=String.length ) maximum number is the longer one

else

take one by one digit from the beginning and compare.

if(string1 digit x = 0 & string 2 digit x=0) go to next digit

if(string1 digit x = 1 & string 2 digit x=0) String 1 is big

if(string1 digit x = 0 & string 2 digit x=1) String 2 is big

Upvotes: 0

upog
upog

Reputation: 5531

try comparing as below

           BigInteger big1 = new BigInteger("01110101010010101010111100010101010101010101010110101010101010101010010101010101010101010101010101111010010101010",2);
           BigInteger big2 = new BigInteger("01110101010010101010111100010101010101010101010110101010101010101010010101010101010101010101010101111010010101010",2);
           int result =big1.compareTo(big2);
           System.out.println(result);

Upvotes: 1

Related Questions