You missed the "non-negative integers" requirement.

Yes, it's not supposed to work, Idk how they validated it!

You have to add brackets as follows :

$"Congratulations! You're going to have a {(sperm == "XY" ? "son" : "daughter")}.";

See Microsoft's documentation about string interpolation using $

what a beautiful solving!

Can someone please explain this problem? Surprised there is 0 comments in all the solutions as I completely don't understand the question nor answer

now i know. ty (Y)

Linq has been a part of C# since version 3. It is not a separate library. Using linq means you are writing functional code. If you are a beginner, you should try writing loops to understand programming but I would never use a loop to find an item in a collection in production code.

everytime i see solutions with using System.Linq;

try without it. sure it is easy with libs.. but sometimes you dont have the possibility

Duplicate issue.

Thanks :D ! I will read about that c:

Func<int,bool> (Func<T,TResult>) is a predefined delegate – a method that has an int parameter and returns a bool. The return type is always the last one in signature and is required for Func<>. And it may be the only type in signature (Func).
In other words, variable is a reference to a value, but delegate is like a reference to a method.
See this: https://docs.microsoft.com/en-us/dotnet/api/system.func-2?view=netframework-4.7.2

Hi! I come from python and i'm starting to learn C#. I grasp the basics and i'm practicing here but there's plenty of things that i don't understand.

Someone can explain me what is this :D ?

Func<int,bool> fun