RemoveDuplicates.cs

static int[] RemoveDuplicates(int[] items)
{
    // Create a new array to store the items with no
    // duplicates
    List<int> newList = new List<int> { items[0] };

    // Loop through every item in our items array
    for (int i = 1; i < items.Length; i++)
    {
        // Create a new boolean to determine whether
        // the item exists in the newList or not
        bool inList = false;
        // Create a counter to loop through newList
        int j = 0;
        // Loop through newList until we reach the
        // end or until we find the item in the list
        while (j < newList.Count && !inList)
        {
            // Check if the current item in newList
            // matches the current item in our items
            // array
            if (items[i] == newList[j])
                // If it does, we know that the item
                // is already in newList and we do not
                // want to add it again
                inList = true;

            j++;
        }

        // Check if the item is in the list or not
        if (!inList)
            // If it is not, add it
            newList.Add(items[i]);
    }

    // Return the newList as an array
    return newList.ToArray();
}