9 simple practices for writing better object-oriented code

Consider a fantasy game that must track a collection of items, each having a certain amount of quality (or value) that increases or decreases after time passes. This collection contains the following six items:

• +5 Dexterity Vest
• Aged Brie
• Elixir of the Mongoose,
• Sulfuras, Hand of Ragnaros
• Backstage passes to a TAFKAL80ETC concert
• Conjured Mana Cake

How much each item’s quality increases or decreases over time depends on an intricate algorithm that involves the quality and sell-in (days) properties of each item. Fortunately a prior C# developer encoded this for us. Let’s see what this algorithm looks like:

private static void UpdateQuality(Item item)
{
    if (item.Name != "Aged Brie" && item.Name != "Backstage passes to a TAFKAL80ETC concert")
    {
        if (item.Quality > 0)
        {
            if (item.Name != "Sulfuras, Hand of Ragnaros")
            {
                item.Quality = item.Quality - 1;
            }
        }
    }
    else
    {
        if (item.Quality < 50)
        {
            item.Quality = item.Quality + 1;
            if (item.Name.Equals("Backstage passes to a TAFKAL80ETC concert"))
            {
                if (item.SellIn < 11)
                {
                    if (item.Quality < 50)
                    {
                        item.Quality = item.Quality + 1…