C# | Random.NextBytes() Method

The NextBytes(Byte[]) method of the System.Random class in C# is used to fill the elements of a specified array of bytes with random numbers. This method takes a byte array as a parameter and fills it with random numbers.

Syntax:

public virtual void NextBytes (byte[] buffer);

Here, buffer is the array of bytes to contain random numbers.

Exception: This method will give ArgumentNullException if the buffer is null.

Below programs illustrates the use of NextBytes() method:

Example 1:

// C# program to illustrate the
// use of Random.NextBytes Method
using System;

class GFG {

    // Driver code
    public static void Main()
    {
        // Instantiate random number generator
        Random rand = new Random();

        // Instantiate an array of byte
        Byte[] b = new Byte[10];

        rand.NextBytes(b);

        // Print random numbers in the byte array
        Console.WriteLine("Printing random numbers"+
                              " in the byte array");

        for (int i = 0; i < 10; i++)
            Console.WriteLine("{0} -> {1}", i, b[i]);
    }
}

Output:

Printing random numbers in the byte array
0 -> 63
1 -> 166
2 -> 5
3 -> 212
4 -> 114
5 -> 94
6 -> 161
7 -> 4
8 -> 226
9 -> 46

Example 2:

// C# program to illustrate the
// use of Random.NextBytes Method
using System;

class GFG {

    // Driver code
    public static void Main()
    {
        // Instantiate random number generator
        Random rand = new Random();

        // Instantiate an array of byte
        Byte[] b = new Byte[10];

        rand.NextBytes(b);

        // Print random numbers in the byte array
        Console.WriteLine("Printing random numbers"+
                              " in the byte array");

        foreach(byte byteValue in b)
            Console.WriteLine("{0}", byteValue);
    }
}

Output:

Printing random numbers in the byte array
98
68
221
160
179
78
172
129
121
179

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.random.nextbytes?view=netframework-4.7.2