Resizing an array using Array.Resize()

in this example I tried to pass an array of nulls (int? [] ) to a function in order to remove all the null values then pass it back to the nullable array.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
int?[] x = new int?[] { 5, null, 3, null, 9, null, null, null, null, 4, null, 3, null, 6 };
Console.WriteLine("---------------------------Null holder array ");
foreach (int? element in x)
{
if(element.HasValue)
Console.WriteLine( element);
else
Console.WriteLine("NULL");
}
Console.WriteLine("my array length " +x.Length);
////I can use nullfree with out no more resize or copy in x array.
int?[] nullfree = function(ref x);
Array.Resize(ref x, nullfree.Length);
Array.Copy(nullfree, x, nullfree.Length);
Console.WriteLine("---------------------------New Null free array ");

foreach (int? element in x)
{
Console.WriteLine(element);
}
Console.WriteLine("my array new length " + x.Length);
}
static int?[] function(ref int?[] x)
{
int size = -1;
int num = 0;
int?[] nullfree = new int?[x.Length];
for (int i = 0; i <>(ref nullfree, size + 1);
return nullfree;
}
}
}