The `long` data type can hold values between roughly -9.2 x 10^{18} and -9.2 x 10^{18}, but sometimes even that range isn’t big enough. The .NET Framework 4.0 (C# 4.0 or Visual Studio 2010) introduced the `BigInteger` structure to represent integer values of arbitrary size.

To use the `BigInteger` data type, add a reference to `System.Numerics`. Then include a `using` statement to make using the `System.Numerics` namespace easy.

The following code shows how the example program uses the `BigInteger` type to calculate large factorials.

// Return N!. private BigInteger BigFactorial(BigInteger N) { if (N < 0) throw new ArgumentException("N must be at leaat 0."); if (N <= 1) return 1; BigInteger result = 1; for (int i = 2; i <= N; i++) result *= i; return result; }

This code can calculate much larger factorials than it could with the `long` data type.

Note that the `BigInteger` type doesn't exist in older versions of the .NET Framework, so the example that's available for download was written in Visual Studio 2012 instead of Visual Studio 2008 as usual.

Im need to biginteger

To use

BigInteger, do the following:System.Numerics.using System.Numerics.Download the example to see additional details.