using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine();

        int a;

        int b;

        Console.Write("Enter a value");

        a = 20;

        Console.WriteLine("The value of a is {0}.", a);

        b = ++a;

        Console.WriteLine("The value of ++a is {0}.", b);

        Console.WriteLine("The value of a is {0}.", a);

        b = a++;

        Console.WriteLine("The value of a++ is {0}.", b);

        Console.WriteLine("The value of a is {0}.", a);

        b = --a;

        Console.WriteLine("The value of --a is {0}.", b);

        Console.WriteLine("The value of a is {0}.", a);

        b = a--;

        Console.WriteLine("The value of a-- is {0}.", b);

        Console.WriteLine("The value of a is {0}.", a);

        Console.ReadLine();

    }

}