表达动态多态性

Question

根据用户输入的动物危险等级，calculate_insurance方法将select正确的大小写和运行计算以确定动物保险的费用. 危险等级在父 class 中设置保险计算是在具有 动态多态性 的 2 个子 class 中通过覆盖父 class 来完成的。解决这个问题的最佳方法是什么？非常感谢您的代码解释

基础class-

public abstract class Animal
{
        protected int danger_rating = 0;

          //get danger rating from user (1-5)
        while (true)
        {
            Console.WriteLine("What is the animals danger rating? \nSelect a number between 1 - 5: "); //Prompt user to type in animals danger rating
            string input = Console.ReadLine(); //reads string input 

            if (int.TryParse(input, out danger_rating)) //convert user string input to int danger_rating
            {
                if (danger_rating == 1) //loop until danger_rating is between 1 and 5
                {
                    break;
                }
                else if (danger_rating == 2)
                {
                    break;
                }
                else if (danger_rating == 3)
                {
                    break;
                }
                else if (danger_rating == 4)
                {
                    break;
                }
                else if (danger_rating == 5)
                {
                    break;
                }
                else
                {
                    Console.WriteLine("Invalid Number. \nNumber must be between 1 - 5");
                }
            }
            else
            {
                Console.WriteLine("This is not a number");
            }

        public virtual double calculate_insurance(int danger_rating)
        {
            return 0;
        } 
}

哺乳动物class -

public class Mammal : Animal //Derived class
{
        public virtual double calculate_insurance(int danger_rating)
        {
            int ins_base = 5000; //base for mammals
            
            double Insurance; //this will contain the output

            //Select case based on danger rating 1 - 5
            switch (danger_rating)
            {
                case 1:
                    Insurance = (ins_base * 10) * 0.02;
                    break;

                case 2:
                    Insurance = (ins_base * 20) * 0.05;
                    break;

                case 3:
                    Insurance = (ins_base * 30) * 0.05;
                    break;

                case 4:
                    Insurance = (ins_base * 40) * 0.05;
                    break;

                case 5:

                    Insurance = (ins_base * 50) * 0.10;
                    break;

                default:
                    Console.WriteLine("Invalid danger rating");
                    break;

            } //end of switch

            return base.calculate_insurance(danger_rating);

        }
}

爬虫类class -

public class Reptile : Animal //Derived class
{
        public virtual double calculate_insurance(int danger_rating)
        {
            int ins_base = 1000; //base for reptiles
            
            double Insurance; //this will contain the output

            //Select case based on danger rating 1 - 5
            switch (danger_rating)
            {
                case 1:
                    Insurance = (ins_base * 10) * 0.02;
                    break;

                case 2:
                    Insurance = (ins_base * 20) * 0.05;
                    break;

                case 3:
                    Insurance = (ins_base * 30) * 0.05;
                    break;

                case 4:
                    Insurance = (ins_base * 40) * 0.05;
                    break;

                case 5:
                    Insurance = (ins_base * 50) * 0.10;
                    break;

                default:
                    Console.WriteLine("Invalid danger rating");
                    break;

            } //end of switch

            return base.calculate_insurance(danger_rating);

        }
}

Answer 1

我不太确定是否有问题需要“解决”，除了在方法级别浮动的 while 循环的基础 class 中的语法错误以及计算保险的一些不可靠之处派生类型的值，然后 return 基本类型的保险计算（即 0）。

哺乳动物和爬行动物中的 calculate_insurance 方法应声明为 override 基本方法，并应以 return Insurance 结尾（注意；应称为 insurance ; 我们不使用 PascalCase 命名局部变量) 不 returning 调用基数的结果..

如果您正在询问如何使用您创建的内容。这种性质的多态性背后的想法是，您可以拥有一个基本类型的变量，而不知道或不关心其中存储的实际类型是什么，因为您只使用基本类型声明存在的功能

Animal a = new Mammal();
a.calculate_insurance(1);  //returns 1000, the rating for a Mammal of type 1

Animal b = new Reptile();
b.calculate_insurance(1);  //returns 200, the rating for a Reptile of type 1

表达动态多态性

Expressing dynamic polymorphism

c#

polymorphism

visual-studio-2019