Fórum ➡ Example of a "crippled" extension method ♦, C#

Language: Layout:

//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;

// aljodav ➡ rextester.com/users/376

// This code is related to the MSDN thread ➡ http://bit.ly/2oPGv27

namespace Rextester
{
    public class Smtg{
        public static Smtg Default(){
            return new Smtg{One="-1-",Two="-2-"};
        }
        public string One,Two;
    }
    
    public static class Util{
        // EXAMPLE of a badly prototyped extension method: CRIPPLED EXTENSION METHOD.
        public static void Set(this Smtg first,ref Smtg second,Smtg third){
            if(first==null||second==null||third==null)throw new Exception("...");
            second.One=first.One;
            second.Two=third.Two;
        }
    }
    
    public class Program
    {
        public static void Write(string msg,Smtg a,Smtg def,Smtg c){
            Console.WriteLine("Exposes the crippled extension method:\n"
                              +"\t\ta ➡ {0}  {1}\n"
                              +"\t de_fault ➡ {2}  {3}\n"
                              +"\t\tc ➡ {4}  {5}\n"
                              +"({6})\n\n",
                              a.One,a.Two,
                              def.One,def.Two,
                              c.One,c.Two,
                              msg
                              );
        }
        
        public static void Main(string[] args)
        {
            Smtg a,de_fault,c;
            
   // 1 ---------------------------------------         
            a=new Smtg{One="Quick",Two="Fox"};
            de_fault=Smtg.Default();
            c=new Smtg{One="HARD",Two="STEEL"};
            //
            de_fault.Set(ref a,c); // crippled extension method
            //
            Write("Notice in the above, that \"a\" changed while \"de_fault\" was kept unchanged!"
                  ,a,de_fault,c);
            
   // 2 ----------------------------------------         
            a=new Smtg{One="Quick",Two="Fox"};
            de_fault=Smtg.Default();
            c=new Smtg{One="HARD",Two="STEEL"};
            //
            de_fault.Set(ref c,a); // crippled extension method
            //
            Write("Notice in the above, that \"c\" changed, while \"de_fault\" was kept unchanged!"
                  ,a,de_fault,c);
            
   // - ------------------------------------------         
            Console.WriteLine("\nHello, world!");
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,16 sec, absolute running time: 0,08 sec, cpu time: 0,08 sec, average memory usage: 12 Mb, average nr of threads: 3