Demo methods to share with student for validating stuff from Console

Validation.cs

static class ConsoleIo
{
    internal static string PromptRequired(string message)
    {
        var res = PromptUser(message);
        while (string.IsNullOrEmpty(res))
        {
            View.DisplayHeader("Input required❗");
            res = PromptUser(message);
        }

        return res;
    }

    internal static decimal PromptUser4Num(string message)
    {
        decimal result;
        while (!decimal.TryParse(PromptUser(message), out result))
        {
            PromptUser("Invalid Input. Press Enter to Continue");
        }

        return result;
    }

    internal static decimal PromptUser4Num(string message, decimal? min, decimal? max)
    {
        decimal result;
        while (!decimal.TryParse(PromptUser(message), out result) || result < min || result > max)
        {
            View.Prompt2Continue(GetErrorMessage(min, max));
        }

        return result;
    }

    internal static DateOnly PromptUser4Date(string message, DateOnly? min, DateOnly? max)
    {
        DateOnly result;
        while (!(DateOnly.TryParse(PromptUser(message), out result)) || (result < min) || (result > max))
        {
            View.Prompt2Continue(GetErrorMessage(min, max));
        }

        return result;
    }

    private static string GetErrorMessage<T>(T? min, T? max)
    {
        string? errorMessage = null;
        if (min != null) errorMessage += $"Invalid Input. Must be after {min.ToString()}❗";
        if (max != null) errorMessage += $"Invalid Input. Must be before {max.ToString()}❗";
        errorMessage ??= "Invalid Input. Press Enter to Continue❗";

        return errorMessage;
    }

    private static string PromptUser(string message)
    {
        Console.Write(message);
        return Console.ReadLine() ?? string.Empty;
    }
}

View.cs

static class View
{    
internal static void DisplayHeader(string header)
    {
        Console.WriteLine(header);
        Console.WriteLine("".PadLeft(header.Length, '='));
    }

    internal static void Prompt2Continue(string message = "Press any key to continue...")
    {
        DisplayHeader(message);
        Console.ReadLine();
    }
}