exception handling - Putting out fires gets old - try/catch/finally

Head First C#:
A Learner's Guide to Real-World Programming
with C# and .NET
Kindle版

開発環境

Head First C Sharp: A Learner’s Guide to Real-World Programming with C Sharp and .NET (Andrew Stellman(著)、Jennifer Greene(著)、O’Reilly Media)の Chapter 12(exception handling - Putting out fires gets old)、p.639(Pool Puzzle)の解答を求めてみる。

コード

Program.cs

using ConsoleApp1;

Kangaroo joey = new();
int koala = joey.Wombat(joey.Wombat(joey.Wombat(1)));
try
{
    Console.WriteLine((15 / koala) + " eggs per pound");
}
catch (DivideByZeroException)
{
    Console.WriteLine("G'Day Mate!");
}

Kangaroo.cs

namespace ConsoleApp1;

public class Kangaroo
{
    FileStream? fs;
    int croc;
    int dingo = 0;
    public int Wombat(int wallaby)
    {
        croc = wallaby;
        try
        {
            if (croc > 0)
            {
                fs = File.OpenWrite("wobbiegong");
                croc = 0;
            }
            else if (croc < 0)
            {
                croc = 3;
            }
            else
            {
                fs = File.OpenRead("wobbiegong");
                croc = 1;
            }
        }
        catch (IOException)
        {
            croc = 3;
        }
        catch
        {
            croc = 4;
        }
        finally
        {
            if (croc > 2)
            {
                croc = dingo;
            }
        }
        return croc;
    }
}

入出力結果(Terminal, Zsh)

% dotnet run
G'Day Mate!
%