Lecture No. 07

Dated: 29-04-2025

Auto Implemented Properties

using System;

public class Customer {
    public int ID { get; set; }
    public string Name { get; set; }
}

public class autoimplementedcustomermanager {
    static void Main () {
        Customer cust = new Customer();
        cust.ID = 1;
        cust.Name = "Amelio Rosales";
        Console.WriteLine(
            "ID: {0}, Name: {1}",
            cust.ID,
            cust.Name);
        Console.ReadKey();
    }
}

Indexer

using System;

class intindexer {
    private string[] mydata;

    public intindexer (int size) {
        mydata = new string[size];

        for (int i = 0; i < size; i++) {
            mydata[i] = "empty";
        }
    }

    public string this[int pos] {
        get {
            return mydata[pos];
        }

        set {
            mydata[pos] = value;
        }
    }

    static void Main (string[] args) {
        int size = 10;
        intindexer myind = new intindexer(size);
        myind[9] = "Some Value";
        myind[3] = "Another Value";
        myind[5] = "Any Value";
        Console.WriteLine("\nindexer Output\n");

        for (int i = 0; i < size; i++) {
            Console.WriteLine("myind[{0}]: {1}", i, myind[i]);
        }
    }
}

Output:

Myind[0]: empty 
Myind[1]: empty 
Myind[2]: empty 
Myind[3]: Another Value 
myind[4]: empty 
Myind[5]: Any Value 
Myind[6]: empty 
Myind[7]: empty 
Myind[8]: empty 
Myind[9]: Some Value

Multiple Parameters

public object this[int param1, ..., int paramn]
{
    get {
        // process and return some class data
    }
    set {
        // process and assign some class data
    }
}

C# built-in types are aliases for .NET Framework types.

Structs

/// <summary>
/// Custom struct type, representing a rectangular shape
/// </summary>
struct Rectangle {
    /// <summary>
    /// Backing Store for Width
    /// </summary>
    private int m_width;
    /// <summary>
    /// Width of rectangle
    /// </summary>
    public int Width {
        get {
            return m_width;
        }
        set {
            M_width = value;
        }
    }
    /// <summary>
    /// Backing store for Height
    /// </summary>
    private int m_height;
    /// <summary>
    /// Height of rectangle
    /// </summary>
    public int Height {
        get {
            return m_height;
        }
        set {
            M_height = value;
        }
    }
}

using System;

/// <summary>
/// Example of declaring and using a struct
/// </summary>
class structexample {
    /// <summary>
    /// Entry point: execution starts here
    /// </summary>
    static void Main () {
        // instantiate a new Rectangle struct
        // where Width is set to 1 and Height is set to 3
        Rectangle rect1 = new Rectangle();
        rect1.Width = 1;
        rect1.Height = 3;
        // show the value of Width and Height for rect1
        Console.WriteLine("rect1: {0}:{1}", rect1.Width, rect1.Height);
        Console.ReadKey();
    }
}

Output:

Rect1: 1:3

// you can also use object initialization syntax
Rectangle rect11 = new Rectangle {
    Width = 1,
    Height = 3
};

Interfaces

interface IMyInterface {
    void MethodToImplement ();
}

using System;

class InterfaceImplementer : IMyInterface {
    static void Main () {
        InterfaceImplementer iimp = new InterfaceImplementer();
        iimp.MethodToImplement();
    }

    public void MethodToImplement () {
        Console.WriteLine("methodtoimplement() called.");
    }
}

Inheritance

using System;

interface IParentInterface {
    void ParentInterfaceMethod ();
}

interface IMyInterface : IParentInterface {
    void MethodToImplement ();
}

class InterfaceImplementer : IMyInterface {
    static void Main () {
        InterfaceImplementer iimp = new InterfaceImplementer();
        iimp.MethodToImplement();
        iimp.ParentInterfaceMethod();
    }

    public void MethodToImplement () {
        Console.WriteLine("methodtoimplement() called.");
    }

    public void ParentInterfaceMethod () {
        Console.WriteLine("parentinterfacemethod() called.");
    }
}