Indexer declaration in C Sharp (C#) - Mini Project: Build & Apply

Indexer Declaration in C#

📖 Scenario: Imagine you are creating a simple class to store and access the names of days in a week by their number. You want to use an indexer so that you can get or set the day name using the day number like an array.

🎯 Goal: Build a class called WeekDays that uses an indexer to get and set day names by their index (0 to 6).

📋 What You'll Learn

Create a class called WeekDays with a private string array of length 7.

Add an indexer to WeekDays that takes an int index and returns or sets the day name at that index.

Use the indexer to set the names of the days from Sunday to Saturday.

Print the day name at index 3 using the indexer.

💡 Why This Matters

🌍 Real World

Indexers let you create classes that behave like arrays or lists, making your code easier to read and use.

💼 Career

Many software jobs require creating custom data structures with indexers to simplify data access and improve code clarity.

1

Create the WeekDays class with a private string array

Create a class called WeekDays with a private string array called days of length 7.

C Sharp (C#)

public class WeekDays
{
    // Your code here
}

Need a hint?

Use private string[] days = new string[7]; inside the class.

2

Add an indexer to get and set day names by index

Inside the WeekDays class, add an indexer with public string this[int index] that gets and sets the value in the days array at index.

C Sharp (C#)

public class WeekDays
{
    private string[] days = new string[7];

    // Add the indexer below
    // Your code here
}

Need a hint?

The indexer looks like a property but uses this[int index].

3

Set the names of the days using the indexer

Create a WeekDays object called week and use the indexer to set the days: Sunday at index 0, Monday at 1, Tuesday at 2, Wednesday at 3, Thursday at 4, Friday at 5, and Saturday at 6.

C Sharp (C#)

public class WeekDays
{
    private string[] days = new string[7];

    public string this[int index]
    {
        get { return days[index]; }
        set { days[index] = value; }
    }
}

WeekDays week = new WeekDays();
// Set the days using the indexer below
// Your code here

Need a hint?

Use week[index] = "DayName"; to set each day.

4

Print the day name at index 3 using the indexer

Write a Console.WriteLine statement to print the day at index 3 from the week object using the indexer.

C Sharp (C#)

public class WeekDays
{
    private string[] days = new string[7];

    public string this[int index]
    {
        get { return days[index]; }
        set { days[index] = value; }
    }
}

WeekDays week = new WeekDays();
week[0] = "Sunday";
week[1] = "Monday";
week[2] = "Tuesday";
week[3] = "Wednesday";
week[4] = "Thursday";
week[5] = "Friday";
week[6] = "Saturday";

Console.WriteLine(week[3]); // Print the day at index 3

Need a hint?

Use Console.WriteLine(week[3]); to print the day at index 3.