Test Your Skills in C# Programming by 2022

Author:2022
Language: eng
Format: epub

Chapter 7 enCapsulation using properties and indexers

return "rectangle";

}

}

Answer:

Here is the output:

Experimenting with an abstract property in C#.

The area of the rectangle is 100 square units.

Explanation:

This program shows how to use an abstract property. In addition, the shape variable

is used polymorphically.

Author’s Note: I said earlier that you can create a property with different types of

modifiers. In this section, we have experimented with two of them: virtual properties and

abstract properties.

The Usage of the init Keyword

7.P7 Can you compile the following code?

Console.WriteLine("Experiment with the 'init' keyword.");

Game game = new();

Console.WriteLine($"Game name: {game.Name}");

class Game

{

private string _name;

public Game() { _name = "SuperGame"; }

public string Name

{

get => _name;

init => _name = value;

}

}

199

Chapter 7 enCapsulation using properties and indexers

Answer:

This code can compile and run successfully. You’ll get the following output:

Experiment with the 'init' keyword.

Game name: SuperGame

Explanation:

You have seen a simple usage of the init accessor for the property called Name. Here

I use a single statement to assign a value; so, I was able to implement the init accessor

as an expression-bodied member.

7.P8 Can you compile the following code?

Console.WriteLine("Experiment with the 'init' keyword.");

Game game = new();

game.Name = "SuperGame2";

class Game

{

private string _name;

public Game() { _name = "SuperGame"; }

public string Name

{

get => _name;

init => _name = value;

}

}

Answer:

No. You’ll receive the following compile-time error that is self-explanatory:

CS8852 Init-only property or indexer 'Game.Name' can only be assigned in

an object initializer, or on 'this' or 'base' in an instance constructor or

an 'init' accessor.

200

Chapter 7 enCapsulation using properties and indexers

7.P9 Can you predict the output of the following code segment?

Game game = new();

Console.WriteLine($"The game name: {game.Name}");

game = new() { Name="Airplane Simulator"};

Console.WriteLine($"The new game name: {game.Name}");

class Game

{

private string _name;

public Game() { _name = "Car Simulator"; }

public string Name

{

get => _name;

init => _name = value;

}

}

Answer:

This code can compile and run successfully. You’ll get the following output:

The game name: Car Simulator

The new game name: Airplane Simulator

Author’s Note: This program demonstrates the usage of object initializer syntax with the init accessor.

7.P10 Can you compile the following code?

Console.WriteLine("A usage of auto-implemented property with

the 'init' keyword.");

Game game = new();

Console.WriteLine($"Game name: {game.Name}");

class Game

{

public string Name { get; init; } = "SuperGame";

}

201

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