简单工厂模式

/// <summary>
/// 简单工厂类
/// </summary>
public class FoodSim
{
    public static Food CreateFood(string str)
    {
        Food food = null;
        if (str == "C1")
        {
            food = new C1();
        }
        else if (str == "C2")
        {
            food = new C2();
        }
        return food;
    }
}
public abstract class Food
{
    public abstract void Print();
}
public class C1 : Food
{
    public override void Print()
    {
        Console.WriteLine("C1");
    }
}
public class C2 : Food
{
    public override void Print()
    {
        Console.WriteLine("C2");
    }
}