超级简单版多态计算器

个人笔记学习黑马四期

一、编写一个操作父类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 多态计算器
{

    /// <summary>
    /// 计算父类
    /// </summary>
    class Operation
    {
        public int NumA { get; set; }
        public int NumB { get; set; }

        public Operation(int numA, int numB)
        {
            this.NumA = numA;
            this.NumB = numB;
        }
        public virtual int GetRes()
        {
            return 0;
        }
    }
}

二、写出加减乘除的类，继承于操作类

加

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 多态计算器
{
    class Add:Operation
    {
        public Add(int numA, int numB)
            : base(numA, numB)
        { 
        
        }
        public override int GetRes()
        {
            return base.NumB+NumA;
        }
    }
}

减

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 多态计算器
{
    class Jian:Operation
    {
        public Jian(int numA, int numB)
            : base(numA, numB)
        { 
        
        }
        public override int GetRes()
        {
            return base.NumA-NumB;
        }
    }
}

乘

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 多态计算器
{
    class Ji:Operation
    {
         public Ji(int numA, int numB)
            : base(numA, numB)
        { 
        
        }
        public override int GetRes()
        {
            return base.NumA*NumB;
        }
    }
}

除

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 多态计算器
{
    class Div:Operation
    {
        public Div(int numA, int numB)
            : base(numA, numB)
        { 
        
        }
        public override int GetRes()
        {
            return base.NumA/NumB;
        }
    }
}

三、写Main

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using 多态计算器;

namespace C09多态计算器
{
    class Program
    {
        static void Main(string[] args)
        {
            //多态是基于继承
            //找父类
            //找子类的共同方法
            //找每个子类的同1个方法，具有不同的实现
            Console.WriteLine("请输入第一个数字");
            int numA = int.Parse(Console.ReadLine());
            Console.WriteLine("请输入第二个数字");
            int numB = int.Parse(Console.ReadLine());
            //
            Console.WriteLine("请输入操作符：1.加 2.减 3.乘 4.除");
            string opt = Console.ReadLine();
            Operation operation=null;

             switch (opt)
             { 
                 case "1":
                     operation=new Add(numA,numB);
                     break;
                 case "2":
                     operation =new Jian(numA,numB);
                     break;
                 case "3":
                     operation=new Ji(numA,numB);
                     break;
                 case "4":
                     operation =new Div(numA,numB);
                     break;

             
             }
            Console.WriteLine(operation.GetRes());
            Console.ReadKey();



        }
    }
}

就好了