Data type in c++ or java for holding 20 digit integer

Question

Is there any data type available in Java or C++ which can hold integer values of 20 digits or more? The long long data type can hold only till 18 digits.

Answer 1

Java specific:

You are looking for BigInteger

Immutable arbitrary-precision integers. All operations behave as if BigIntegers were represented in two's-complement notation (like Java's primitive integer types)

For ex:

  BigInteger bint = new BigInteger("1234567856656569");
  BigInteger bint2 = new BigInteger("1234556567856656569");
  System.out.println(bint2.intValue()-bint.intValue()); //397189120

And BigDecimal

Answer 2

Take a look at java BigInteger.

Answer 3

In java you can use:

• BigInteger: for numbers without decimal values
• BigDecimal: for numbers with decimal values

Answer 4

Check out The Large Integer Case Study in C++.pdf by Owen Astrachan. I found this file extremely useful with detail introduction and code implementation. It doesn't use any 3rd-party library. I have used this to handle huge numbers (as long as you have enough memory to store vector<char>) with no problems.

I have answered a similar question here, where I gave a more detailed introduce.

Answer 5

For C++, you can check out Matt McCutchen's Big Integer class, for Java just use BigInteger

Answer 6

BigInteger class in Java can hold such numbers.

Alternatively, you can implement your own class, based on two long long numbers.

Answer 7

For C++, see Boost's excellent multiprecision library.

Answer 8

Use BigInt datatype with its implicit operations

Here is an example of addition

      BigInteger big1 = new BigInteger("1234567856656567242177779");
      BigInteger big2 = new BigInteger("12345565678566567131275737372777569");
      BigInteger bigSum = big1.add(big2);
      System.out.println(bigSum );