Initialize a byte array to a certain value, other than the default null?

Question

I'm busy rewriting an old project that was done in C++, to C#.

My task is to rewrite the program so that it functions as close to the original as possible.

During a bunch of file-handling the previous developer who wrote this program creates a structure containing a ton of fields that correspond to the set format that a file has to be written in, so all that work is already done for me.

These fields are all byte arrays. What the C++ code then does is use memset to set this entire structure to all spaces characters (0x20). One line of code. Easy.

This is very important as the utility that this file eventually goes to is expecting the file in this format. What I've had to do is change this struct to a class in C#, but I cannot find a way to easily initialize each of these byte arrays to all space characters.

What I've ended up having to do is this in the class constructor:

//Initialize all of the variables to spaces.
int index = 0;
foreach (byte b in UserCode)
{
    UserCode[index] = 0x20;
    index++;
}

This works fine, but I'm sure there must be a simpler way to do this. When the array is set to UserCode = new byte[6] in the constructor the byte array gets automatically initialized to the default null values. Is there no way that I can make it become all spaces upon declaration, so that when I call my class' constructor that it is initialized straight away like this? Or some memset-like function?

Answer 1

For small arrays use array initialisation syntax:

var sevenItems = new byte[] { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20 };

For larger arrays use a standard for loop. This is the most readable and efficient way to do it:

var sevenThousandItems = new byte[7000];
for (int i = 0; i < sevenThousandItems.Length; i++)
{
    sevenThousandItems[i] = 0x20;
}

Of course, if you need to do this a lot then you could create a helper method to help keep your code concise:

byte[] sevenItems = CreateSpecialByteArray(7);
byte[] sevenThousandItems = CreateSpecialByteArray(7000);

// ...

public static byte[] CreateSpecialByteArray(int length)
{
    var arr = new byte[length];
    for (int i = 0; i < arr.Length; i++)
    {
        arr[i] = 0x20;
    }
    return arr;
}