Null-coalescing operator in C Sharp (C#) - Mini Project: Build & Apply

Using the Null-coalescing Operator in C#

📖 Scenario: Imagine you are building a simple program that greets users. Sometimes, the user's name might not be provided, so you want to use a default greeting name instead.

🎯 Goal: You will create a program that uses the null-coalescing operator (??) to provide a default name when the user's name is missing.

📋 What You'll Learn

Create a string variable called userName with a null value.

Create a string variable called defaultName with the value "Guest".

Use the null-coalescing operator ?? to assign a variable nameToUse either userName if it is not null, or defaultName if userName is null.

Print the greeting message Hello, {nameToUse}!.

💡 Why This Matters

🌍 Real World

In real applications, user input or data from databases can be missing or null. The null-coalescing operator helps provide safe default values to avoid errors.

💼 Career

Understanding how to handle null values safely is important for writing robust C# programs, especially in web development and data processing jobs.

1

Create the userName variable with a null value

Create a string variable called userName and set it to null.

C Sharp (C#)

# Your code here

Need a hint?

Use string? userName = null; to allow userName to be null.

2

Create the defaultName variable

Create a string variable called defaultName and set it to "Guest".

C Sharp (C#)

string? userName = null;
# Your code here

Need a hint?

Use string defaultName = "Guest"; to set the default name.

3

Use the null-coalescing operator to assign nameToUse

Create a string variable called nameToUse and assign it the value of userName ?? defaultName using the null-coalescing operator.

C Sharp (C#)

string? userName = null;
string defaultName = "Guest";
# Your code here

Need a hint?

Use ?? to choose userName if not null, otherwise defaultName.

4

Print the greeting message

Write a Console.WriteLine statement to print Hello, {nameToUse}! using string interpolation.

C Sharp (C#)

string? userName = null;
string defaultName = "Guest";
string nameToUse = userName ?? defaultName;
# Your code here

Need a hint?

Use Console.WriteLine($"Hello, {nameToUse}!"); to print the greeting.