Polymorphism example, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    //Polymorphism
    class CTPM
    {
       public void add(int a,int b)
       {
           Console.WriteLine("Addition "+(a+b));
       }
         public void add(int a,int b,int c)
       {
           int d=a+b+c;
           Console.WriteLine("Addition "+d);
       }
    }
    
    class RTPM
    {
       public virtual void display()
       {
           Console.WriteLine("Physical memory of RTPM");
       }
    }
    
    class MVR:RTPM
    {
       public override void display()
       {
           Console.WriteLine("Logical memory of RTPM in MVR");
       }
        
    }
    public class Program
    {
        public static void Main(string[] args)
        {
            //complie time polymorphism methods calling
          CTPM obj=new CTPM();
            obj.add(5,4);
            obj.add(3,9,7);
            //Runtime Polymorphism
            
            MVR obj1=new MVR();
            obj1.display();
            RTPM r=new RTPM();
            r.display();
            
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,12 sec, absolute running time: 0,08 sec, cpu time: 0,08 sec, average memory usage: 12 Mb, average nr of threads: 3