Program:

The source code to produce a third array by appending two different arrays in C# is given below. The given program is compiled and executed successfully on Microsoft Visual Studio.

//Program to produce a third array by 
//appending two different arrays in C#.

using System;

class Demo
{
    static void Main()
    {
        int[] intArr1   = {1,2,3,4,5};
        int[] intArr2   = {6,7,8,9,0};
        int[] intArr3   = new int[10];

        int totalLengthInBytes = 0;

        totalLengthInBytes = intArr1.Length * sizeof(int);
        Buffer.BlockCopy(intArr1, 0, intArr3, 0, totalLengthInBytes);

        totalLengthInBytes = intArr2.Length * sizeof(int);
        Buffer.BlockCopy(intArr2, 0, intArr3, totalLengthInBytes, totalLengthInBytes);

        foreach (int items in intArr3)
        {
            Console.Write(items+ " ");
        }
        Console.WriteLine();
    }
}

Output:

1 2 3 4 5 6 7 8 9 0
Press any key to continue . . .

Explanation:

In the above program, we created three arrays intArray1, intArray2, and intArray3. The intArray1 and intArray2 contain 5 items and we occupied space of 10 items for intArray3.

int totalLengthInBytes = 0;

totalLengthInBytes = intArr1.Length * sizeof(int);
Buffer.BlockCopy(intArr1, 0, intArr3, 0, totalLengthInBytes);

totalLengthInBytes = intArr2.Length * sizeof(int);
Buffer.BlockCopy(intArr2, 0, intArr3, totalLengthInBytes, totalLengthInBytes);

In the above code, we copied intArray1 to intArray3 and then appended intArray2 into intArray3 using BlockCopy() method.

foreach (int items in intArr3)
{
    Console.Write(items+ " ");
}

The above code will print all elements of intArray3 on the console screen.