c# - 不能声明主体，因为它被标记为抽象

Question

您好，我是 C# 控制台应用程序的新手，我正在使用抽象和覆盖，但我在 public abstract double Compute() 的第一个方法中得到了堆栈，我得到了一个错误，它说 < strong>无法声明正文，因为它被标记为抽象请帮助我。谢谢你!

`

abstract class Cake
    {
        public string _flavor, _size;
        public int _quantity;

        public Cake(string flavor, string size, int quantity)
        {
            _flavor = flavor;
            _size = size;
            _quantity = quantity;
        }

        public abstract double Compute()
        {
            double price;
            if(_flavor == "Chocolate" && _size == "Regular")
            {
               price = 250.50;
            }
            else if (_flavor == "Chocolate" && _size == "Large")
            {
                price = 450.50;
            }
            else if (_flavor == "Strawberry" && _size == "Regular")
            {
                price = 300.50;
            }
            else
            {
                price = 500.75;
            }
            return price;
        }
    }

    class BirthdayCake:Cake
    {
        public int _numOfCandles;

        public BirthdayCake(string flavor, string size, int quantity, int numOfCandles):base(flavor,size,quantity)
        {
            _numOfCandles = numOfCandles;
        }

        public override double Compute()
        {
            return _numOfCandles * 10.00;
        }
    }`

Answer 1

当您有默认实现但希望允许子类时，请使用virtual 而不是abstract覆盖