`BigInteger`

Occasionally large integers are needed in VB.NET programs, even ones that exceed the maximum value of a double. BigInteger can accommodate these values.

By calling New, we can create a BigInteger from a Double. And with Add() we combine two BigIntegers and receive another BigInteger. We call ToString() to convert a BigInteger to a String.

Example

To create a BigInteger, we need to call the New Function, which is the constructor. We can pass a value like a Double to the New Function.

Step 1 We create the BigIntegers needed for the code example from the Double.MaxValue constant.

Step 2 The BigInteger Class has a Shared Add() Function on it, and this function adds its two arguments together.

Step 3 We use string interpolation to print out the values. We have doubled the Double.MaxValue, which would not fit inside an actual Double.

Step 4 A BigInteger can contain 309 digits, and even more, without issues. This is truly a large numeric type.

Imports System.Numerics

Module Module1
    Sub Main()
        ' Step 1: create 2 BigIntegers, based on double.MaxValue.
        Dim big1 As BigInteger = New BigInteger(Double.MaxValue)
        Dim big2 As BigInteger = New BigInteger(Double.MaxValue)

        ' Step 2: call Add() to add the BigIntegers.
        Dim result As BigInteger = BigInteger.Add(big1, big2)

        ' Step 3: print out the values.
        Console.WriteLine($"DOUBLE MAX: {big1}")
        Console.WriteLine($"DOUBLE MAX * 2: {result}")

        ' Step 4: print the digit count of the BigInteger.
        Console.WriteLine($"DIGITS: {result.ToString().Length}")
    End Sub
End ModuleDOUBLE MAX: 179769313486...50404026184124858368
DOUBLE MAX * 2: 359538626972...500808052368249716736
DIGITS: 309

When a Double is not enough for a certain numeric type, consider the BigInteger type, which can handle much larger numbers. It is not going to help performance if used extensively in hot loops.