Properties in C#: A Complete Guide

 // C# program to illustrate the problems
 // with public and private members
using System;

// public class
public class C1
     { 
     // public data members
       public int rn;
       public string name; 
     // private field
     // private int marks = 35;
     }
 // another public class
  public class C2
         { 
      // Main Method
    public static void Main(string[] args)
    { 
    // Creating object of C1 class
     C1 obj = new C1(); 
    // setting values to public
     // data members of class C1
   obj.rn = 10000;
   obj.name = null;
   // setting values to private
  // data members of class C1
   // obj.mark = 0;
   // display result
     Console.WriteLine("Name: {0} \nRoll No: {1}", obj.name, obj.rn);
          }
    }   

 Name:
Roll No: 10000

  class Scholar {
          // Declare roll_no field
            private int roll_no;
          // Declare roll_no property
     public int Roll_no 
           { 
       get 
             {
             return roll_no;
             }
          }
        }   

  class Scholar {
              // Declare roll_no field
                private int roll_no;
             // Declare roll_no property
            public int Roll_no
               { 
                get 
                    {
                       return roll_no;
                     }
              set 
                 {
             roll_no = value;
          }
       }
     }    

 using System;

class Student
{
    // Private field
    private string _name;

    // Read-only property
    public string Name
    {
        get { return _name; }
    }

    // Constructor to set the read-only property
    public Student(string name)
    {
        _name = name;
    }
}

class Program
{
    static void Main()
    {
        Student student = new Student("Ankita");
        Console.WriteLine("Student Name: " + student.Name);

        // The following line will give an error because the property is read-only:
        // student.Name = "Rahul";  // Uncommenting this will cause a compilation error.
    }
}

 Student Name: Ankita

 using System;

class Employee
{
    // Private field
    private decimal _salary;

    // Write-only property
    public decimal Salary
    {
        set { _salary = value; }
    }

    // Method to display salary (could be restricted in real-world scenarios)
    public void DisplaySalary()
    {
        Console.WriteLine("Salary: " + _salary);
    }
}

class Program
{
    static void Main()
    {
        Employee employee = new Employee();

        // Setting the salary using the write-only property
        employee.Salary = 50000m;

        // Displaying the salary using a method (read access is not allowed directly)
        employee.DisplaySalary();

        // The following line would cause an error because the property is write-only:
        // Console.WriteLine(employee.Salary);  // Uncommenting this will cause a compilation error.
    }
}  

 Salary: 50000

 public <data_type> PropertyName { get; set; }

 using System;

class Car
{
    // Auto-implemented property for CarName
    public string CarName { get; set; }

    // Auto-implemented property with default value
    public int ModelYear { get; set; } = 2024;
}

class Program
{
    static void Main()
    {
        // Creating an object of Car class
        Car myCar = new Car();

        // Setting value to auto-implemented property
        myCar.CarName = "Honda";

        // Getting value from auto-implemented property
        Console.WriteLine("Car Name: " + myCar.CarName);

        // Getting auto-implemented property with default value
        Console.WriteLine("Model Year: " + myCar.ModelYear);
    }
}  

 Car Name: Honda
Model Year: 2024

 using System;

class Bank
{
    // Static property
    public static decimal InterestRate { get; set; }

    // Instance method to display the interest rate
    public void DisplayInterestRate()
    {
        Console.WriteLine("Current Interest Rate: " + InterestRate + "%");
    }
}

class Program
{
    static void Main()
    {
        // Setting the static property using the class name
        Bank.InterestRate = 4.5m;

        // Creating instances of the Bank class
        Bank bank1 = new Bank();
        Bank bank2 = new Bank();

        // Displaying the static property (same for all instances)
        bank1.DisplayInterestRate();
        bank2.DisplayInterestRate();

        // Updating the static property
        Bank.InterestRate = 5.0m;

        // Displaying the updated interest rate
        bank1.DisplayInterestRate();
        bank2.DisplayInterestRate();
    }
}   

 Current Interest Rate: 4.5%
Current Interest Rate: 4.5%
Current Interest Rate: 5.0%
Current Interest Rate: 5.0%

 using System;

abstract class Shape
{
    // Abstract property for calculating the area
    public abstract double Area { get; }

    // Abstract property for calculating the perimeter
    public abstract double Perimeter { get; }
}

class Circle : Shape
{
    private double radius;

    // Constructor to initialize the radius
    public Circle(double radius)
    {
        this.radius = radius;
    }

    // Implementing the abstract Area property
    public override double Area
    {
        get { return Math.PI * radius * radius; }
    }

    // Implementing the abstract Perimeter property
    public override double Perimeter
    {
        get { return 2 * Math.PI * radius; }
    }
}

class Program
{
    static void Main()
    {
        // Creating a Circle object
        Circle circle = new Circle(5);

        // Accessing the implemented properties
        Console.WriteLine("Circle Area: " + circle.Area);
        Console.WriteLine("Circle Perimeter: " + circle.Perimeter);
    }
}  

 Circle Area: 78.53981633974483
Circle Perimeter: 31.41592653589793

 using System;

class Animal
{
    // Virtual property allows overriding in derived classes
    public virtual string Sound { get; set; }

    // Method to describe the sound
    public void MakeSound()
    {
        Console.WriteLine("Animal makes sound: " + Sound);
    }
}

class Dog : Animal
{
    // Overriding the Sound property
    public override string Sound
    {
        get { return "Bark"; }
    }
}

class Cat : Animal
{
    // Overriding the Sound property
    public override string Sound
    {
        get { return "Meow"; }
    }
}

class Program
{
    static void Main()
    {
        // Polymorphism using base class reference and derived class objects
        Animal myAnimal;

        myAnimal = new Dog();
        myAnimal.MakeSound();  // Output: Animal makes sound: Bark

        myAnimal = new Cat();
        myAnimal.MakeSound();  // Output: Animal makes sound: Meow
    }
}  

 Animal makes sound: Bark
Animal makes sound: Meow

 using System;

class Vehicle  // Base class
{
    public string Brand { get; set; }

    // Method in the base class
    public void StartEngine()
    {
        Console.WriteLine(Brand + " engine started.");
    }
}

// Derived class inheriting from Vehicle
class Car : Vehicle
{
    public string Model { get; set; }

    // Method in the derived class
    public void DisplayInfo()
    {
        Console.WriteLine("Brand: " + Brand + ", Model: " + Model);
    }
}

class Program
{
    static void Main()
    {
        // Creating an instance of the derived class
        Car myCar = new Car();

        // Accessing base class members from the derived class
        myCar.Brand = "Honda";  // Inherited from Vehicle
        myCar.Model = "Civic";  // Specific to Car

        // Calling methods
        myCar.StartEngine();    // Inherited method from Vehicle
        myCar.DisplayInfo();    // Method in Car class
    }
}   

 Honda engine started.
Brand: Honda, Model: Civic