Default keyword for generic types in C Sharp (C#) - Mini Project: Build & Apply

Using the Default Keyword with Generic Types in C#

📖 Scenario: Imagine you are creating a simple program that works with different types of data. Sometimes, you need to set a variable to its default value without knowing its exact type in advance.

🎯 Goal: You will build a small C# program that uses the default keyword with generic types to assign default values to variables of different types.

📋 What You'll Learn

Create a generic method that returns the default value of its type parameter.

Call this method with different types like int, string, and a custom class.

Print the default values to the console.

💡 Why This Matters

🌍 Real World

Using the <code>default</code> keyword with generics helps write flexible code that works with many types without knowing them in advance.

💼 Career

Understanding generics and default values is important for writing reusable and safe code in C# software development.

1

Create a generic method to return default value

Write a generic method called GetDefaultValue with a type parameter T that returns default(T).

C Sharp (C#)

// Your code here

Need a hint?

Use default(T) inside the method to get the default value of the generic type.

2

Call the generic method with different types

Inside the Main method, create three variables: intDefault assigned to GetDefaultValue<int>(), stringDefault assigned to GetDefaultValue<string>(), and customDefault assigned to GetDefaultValue<MyClass>(). Also, define an empty class called MyClass outside Program.

C Sharp (C#)

using System;

class Program
{
    public static T GetDefaultValue()
    {
        return default(T);
    }

    static void Main()
    {
        // Your code here
    }
}

// Your code here

Need a hint?

Call GetDefaultValue with the type inside angle brackets <> and assign the result to variables.

3

Print the default values to the console

Add Console.WriteLine statements inside Main to print intDefault, stringDefault, and customDefault. Use ?? "null" to show "null" for reference types.

C Sharp (C#)

using System;

class Program
{
    public static T GetDefaultValue()
    {
        return default(T);
    }

    static void Main()
    {
        int intDefault = GetDefaultValue();
        string stringDefault = GetDefaultValue();
        MyClass customDefault = GetDefaultValue();
        // Print the default values below
        // Your code here
    }
}

class MyClass
{
}

Need a hint?

Use ?? "null" to print "null" if the value is null.

4

Run the program and see the output

Run the program to see the printed default values for int, string, and MyClass.

C Sharp (C#)

using System;

class Program
{
    public static T GetDefaultValue()
    {
        return default(T);
    }

    static void Main()
    {
        int intDefault = GetDefaultValue();
        string stringDefault = GetDefaultValue();
        MyClass customDefault = GetDefaultValue();

        Console.WriteLine(intDefault);
        Console.WriteLine(stringDefault ?? "null");
        Console.WriteLine(customDefault ?? "null");
    }
}

class MyClass
{
}

// Run the program to see the output

Need a hint?

The default value for int is 0, and for reference types like string and MyClass it is null.