Classes Student + Teacher C# Exercise - C# Programming Course

// Import the System namespace for basic functionality
using System;

// Define the base class Person
public class Person
{
    // Declare a public integer field for age
    public int age;

    // Define a public method to set the age of the person
    public void SetAge(int n)
    {
        // Assign the value of n to the age field
        age = n;
    }

    // Define a public method for greeting
    public void Greet()
    {
        // Print a greeting message to the console
        Console.WriteLine("Hello!");
    }
}

// Define the derived class Student, inheriting from Person
public class Student : Person
{
    // Define a public method that indicates the student is going to classes
    public void GoToClasses()
    {
        // Print a message to indicate going to class
        Console.WriteLine("I'm going to class.");
    }

    // Define a public method to show the student's age
    public void ShowAge()
    {
        // Print the age message with the current age
        Console.WriteLine("My age is: " + age + " years old.");
    }
}

// Define the derived class Teacher, inheriting from Person
public class Teacher : Person
{
    // Declare a private string field for the subject
    private string subject;

    // Define a public method that indicates the teacher is explaining
    public void Explain()
    {
        // Print a message to indicate that an explanation is beginning
        Console.WriteLine("Explanation begins.");
    }

    // Define a method to set the teacher's subject
    public void SetSubject(string subjectName)
    {
        // Assign the value of subjectName to the subject field
        subject = subjectName;
    }
}

// Define a test class to execute the program
public class StudentAndTeacherTest
{
    // Main method to run the program
    public static void Main()
    {
        // Create a Person object and make it say hello
        Person person = new Person();
        person.Greet();

        // Create a Student object, set its age, greet, and show its age
        Student student = new Student();
        student.SetAge(21);
        student.Greet();
        student.ShowAge();
        student.GoToClasses();

        // Create a Teacher object, set its age, greet, and explain
        Teacher teacher = new Teacher();
        teacher.SetAge(30);
        teacher.Greet();
        teacher.Explain();
    }
}