Zero padding a 2D array in C#-CodePudding

I currently have an issue with zero padding my 2d Array. I want to transfer my current data in my array to a new array, which is the exact same array but with a border of 0's around it. Example:

|1 2 3|

|4 5 6|

|7 8 9|

Should become

|0 0 0 0 0|

|0 1 2 3 0|

|0 4 5 6 0|

|0 7 8 9 0|

|0 0 0 0 0|

 int[,] Array = new int[,] { { 1, 2, 3 }, { 3, 4, 5 }, { 6, 7, 8 } };
        
        int[,] ArrayZeroPad = new int[Array.GetLength(0)   2, Array.GetLength(1)   2];
        for (int y = 0; y < Array.GetLength(1); y  )
        {

            for (int x = 0; x < ArrayZeroPad.GetLength(0); x  )
            {
                if (y == 0)
                { ArrayZeroPad[y, x] = 0; }
                else if (y == ArrayZeroPad.GetLength(1))
                { ArrayZeroPad[y, x] = 0; }
                else if (x == 0)
                {
                    ArrayZeroPad[y, x] = 0;

                }
                else if (x == ArrayZeroPad.GetLength(0))
                { ArrayZeroPad[y, x] = 0; }
                else ArrayZeroPad[y, x] = Array[y, x];
            }
        }
        for (int y = 0; y < ArrayZeroPad.GetLength(1); y  )
        {
            Console.WriteLine();
            for (int x = 0; x < ArrayZeroPad.GetLength(0); x  )
            { Console.Write(ArrayZeroPad[y, x]); }
            Console.ReadLine();
        }
    }

This is what I have come to thus far, but I keep getting stuck on out of bounds errors, is there anyone who could work this out for me with some explanation?

Kind regards, D.

CodePudding user response：

        int[,] Array = new int[,] { { 1, 2, 3 }, { 3, 4, 5 }, { 6, 7, 8 } };
        int[,] ArrayZeroPad = new int[Array.GetLength(0)   2, Array.GetLength(1)   2];

        for (int x = 0; x < ArrayZeroPad.GetLength(0); x  )
        {
            for (int y = 0; y < ArrayZeroPad.GetLength(0); y  )
            {
                //First row and last row
                if (x == 0 || x == ArrayZeroPad.GetLength(0) - 1)
                    ArrayZeroPad[x, y] = 0;
                else
                {
                    //Fist column and last column
                    if (y == 0 || y == ArrayZeroPad.GetLength(0) - 1)
                        ArrayZeroPad[x, y] = 0;
                    else
                    {
                        //Content
                        ArrayZeroPad[x, y] = Array[x-1, y-1];
                    }
                }
            }
        }

CodePudding user response：

It seems that you are confusing dimensions - Array.GetLength(0) is for the first one in access Array[i, j] and Array.GetLength(1) is for the second. Also you can simplify copy by just scanning through Array elements and adjusting destination indexes by one, you don't need to explicitly set others to 0 cause it would be done for you (unless you are using stackalloc and skipping local init but I highly doubt that this is the case):

var length0 = Array.GetLength(0);
var length1 = Array.GetLength(1);
for (int i = 0; i < length0; i  )
{
    for (int j = 0; j < length1; j  )
    {
        ArrayZeroPad[i   1, j   1] = Array[i, j];
    }
}

And in the "print" method too - y should be the first dimension and x - second:

var length = ArrayZeroPad.GetLength(0);
for (int y = 0; y < length; y  )
{
    Console.WriteLine();
    var i = ArrayZeroPad.GetLength(1);
    for (int x = 0; x < i; x  )
    {
        Console.Write(ArrayZeroPad[y, x]);
    }
    Console.ReadLine();
}