using System;   

​

public class Professor

{

    // Public

    public string ProfessorName;

    // Private

    private int Age;

    // Properties

    public int iInput

    {

        get

        {

            return Age;

        }

        set

        {

            if (value > 18 && value < 70) {

            Age = value;

            }

            else {

            Age = 30;

            }

        }

    }

    // Default Constructor

    public Professor()

    {

    }

}

​

public class Program

{

    public static void Main()

    {

        // Create Object

        Professor professor1 = new Professor();

        professor1.ProfessorName = "Liu";

        professor1.iInput = 18;

        // Print Object

        Console.WriteLine("Professor Name: " + professor1.ProfessorName);

        Console.WriteLine("Age: " + professor1.iInput);

    }

}