How to use BigInteger in C# 4.0

Introduction

In this tip, I will explain how to use the BigInteger in C# 4.0.The BigInteger is new data type in .NET 4.0.During programming some complex systems often we need a very big numbers. For example if we use some of asymmetrical cryptographic feature which require to use large numbers or we can give simple example of factorial where we sometime reached to limit of data type provided by C# compiler. At that time this BigInteger data type can be very handy. You can store 232 to 264 number in this data type. So its very big and you can copy very very big number in that data type.

So let’s take a simple example to write a factorial program. BigInteger data type comes under System.Numerics namespace. So first we have to add reference to our program to System.Numerics assembly like following.

Now we have added the reference to System.Numeric so we are ready for code. Here in code I have just taken a very large number in big integer which is out of range of integer to test out. So I have assigned ‘39242937852522522’ to big integer object and printed that. Following is a code for that.

using System;
using System.Numerics;
 
namespace ExperimentConsole
{
    class Program
    {
        static void Main(string[] args)
        {
            BigInteger n = 39242937852522522;
            Console.WriteLine(n);
        }
    }
}

Let’s run code and see output like following as expected its printing value.

If you are run same program with integer it will not compile. It will give ‘Can not covert type long to integer error’. That’s it. Hope you liked it.