แบบฝึกหัด C#

Nullable User Profile

Nullable reference annotations and null operators make absence explicit.

How it works

Safely display optional profile data.

The conditional access and coalescing operators avoid dereferencing a missing nickname.

Runnable C# example

Program.cs

using System;
record Profile(string Name, string? Nickname);
class Program
{
    static void Main()
    {
        var profile = new Profile("Ada", null);
        Console.WriteLine(profile.Nickname?.ToUpperInvariant() ?? profile.Name);
    }
}

Expected output

Ada

Practice with the debugger

Set a breakpoint on an important assignment or condition, click Debug, and inspect the local values before stepping to the next line.