Multi-parameter indexers in C Sharp (C#) - Mini Project: Build & Apply

Using Multi-parameter Indexers in C#

📖 Scenario: Imagine you manage a small hotel with rooms on different floors. You want to keep track of which guest is staying in each room using a simple system.

🎯 Goal: You will create a class with a multi-parameter indexer that lets you get and set guest names by specifying the floor and room number.

📋 What You'll Learn

Create a class called Hotel that stores guest names.

Use a multi-parameter indexer with two int parameters: floor and room.

The indexer should allow getting and setting guest names by floor and room.

Demonstrate setting and getting guest names using the indexer.

💡 Why This Matters

🌍 Real World

Multi-parameter indexers are useful when you want to access data stored in a grid or table-like structure, such as seats in a theater, cells in a spreadsheet, or rooms in a hotel.

💼 Career

Understanding multi-parameter indexers helps you write cleaner and more intuitive code when working with complex data structures, a common task in software development jobs.

1

Create the Hotel class with a 2D array

Create a class called Hotel with a private 2D string array called guests sized 3 floors by 5 rooms each. Initialize the array in the constructor.

C Sharp (C#)

public class Hotel
{
    // Your code here
}

Need a hint?

Use a 2D array to store guest names by floor and room.

2

Add a multi-parameter indexer to the Hotel class

Inside the Hotel class, add a public indexer with two int parameters named floor and room. The indexer should get and set values in the guests array.

C Sharp (C#)

public class Hotel
{
    private string[,] guests;

    public Hotel()
    {
        guests = new string[3, 5];
    }

    // Add multi-parameter indexer here
}

Need a hint?

Use this[int floor, int room] to define the indexer with get and set accessors.

3

Create a Hotel object and assign guest names

In the Main method, create a Hotel object called myHotel. Use the indexer to assign "Alice" to floor 0, room 1 and "Bob" to floor 2, room 4.

C Sharp (C#)

public class Hotel
{
    private string[,] guests;

    public Hotel()
    {
        guests = new string[3, 5];
    }

    public string this[int floor, int room]
    {
        get { return guests[floor, room]; }
        set { guests[floor, room] = value; }
    }
}

class Program
{
    static void Main()
    {
        // Create Hotel object and assign guests
        // Your code here
    }
}

Need a hint?

Create the object and use the indexer with two numbers inside square brackets to assign names.

4

Print guest names using the multi-parameter indexer

In the Main method, add two Console.WriteLine statements to print the guests at floor 0, room 1 and floor 2, room 4 using the indexer on myHotel.

C Sharp (C#)

public class Hotel
{
    private string[,] guests;

    public Hotel()
    {
        guests = new string[3, 5];
    }

    public string this[int floor, int room]
    {
        get { return guests[floor, room]; }
        set { guests[floor, room] = value; }
    }
}

class Program
{
    static void Main()
    {
        Hotel myHotel = new Hotel();
        myHotel[0, 1] = "Alice";
        myHotel[2, 4] = "Bob";
        // Print guest names
        // Your code here
    }
}

Need a hint?

Use Console.WriteLine(myHotel[0, 1]) and Console.WriteLine(myHotel[2, 4]) to print the guest names.