C#

Member 15634071 wrote:

in CE (Central Europe) where I live it is comma

public static class Complex2
 {
     public static Complex ComplexParse(string text)   // (x, y) or (x+yi) or (x+yj) or (x-yi) or (x-yj)
     {
         string[] parts;
         string parsedText = text.Trim();
         if (parsedText.StartsWith("(") && parsedText.EndsWith(")"))
         {
             parsedText = parsedText.Substring(1, parsedText.Length - 2).Trim(); // Drop parentheses
             if (parsedText.Contains("+") && (parsedText.EndsWith("i") || parsedText.EndsWith("j")))
             {
                 parts = parsedText.Split('+');
                 if (parts.Length == 2)
                     return
                         new Complex(
                             real: double.Parse(parts[0].Trim()),
                             imaginary: double.Parse(parts[1].Substring(0, parts[1].Length - 1).Trim())
                             );

                 throw new ArgumentException("Complex number format not recognised (multiple '+' chars)");
             }
             else if (parsedText.Substring(1).Contains("-") && (parsedText.EndsWith("i") || parsedText.EndsWith("j")))   // (x-yi) or (x-yj) // Beware of (-x-yi) or (-x-yj)
             {
                 parts = parsedText.Substring(1).Split('-');
                 if (parts.Length == 2)
                     return
                         new Complex(
                             real: double.Parse(parsedText.Substring(0, 1) + parts[0].Trim()),
                             imaginary: -double.Parse(parts[1].Substring(0, parts[1].Length - 1).Trim())
                             );

                 throw new ArgumentException("Complex number format not recognised (multiple '+' chars)");
             }
             else if (parsedText.Contains(","))  // Hopefully in the form x, y
             {
                 parts = parsedText.Split(',');
                 if (parts.Length == 2)
                     return
                         new Complex(
                             real: Double.Parse(parts[0].Trim()),
                             imaginary: Double.Parse(parts[1].Trim())
                             );

                 // Too many commas. Can only diambiguate if one is followed by a space
                 int ix = parsedText.IndexOf(", ");
                 if (ix < 1)     // ", " not found or there is an empty real part
                     throw new ArgumentException("Complex number format not recognised (ambiguous use of commas)");

                 return
                     new Complex(
                         real: double.Parse(parsedText.Substring(0, ix).Trim()),
                         imaginary: double.Parse(parsedText.Substring(ix + 1).Trim())
                         );
             }
             else
                 throw new ArgumentException("Complex number format not recognised");
         }
         else
             throw new ArgumentException("Complex number not enclosed in parentheses");
     }

     public static bool ComplexTryParse(string text, out Complex ComplexOut)
     {
         try
         {
             ComplexOut = ComplexParse(text);
             return true;
         }
         catch (Exception)
         {
             ComplexOut = new Complex(0.0, 0.0);
             return false;
         }
     }
 }

public static class StringExtensions
 {
     public static Complex ComplexParse(this string fromText) =>
         Complex2.ComplexParse(fromText);

     public static bool ComplexTryParse(this string fromText, out Complex result) =>
         Complex2.ComplexTryParse(fromText, out result);
 }

class Program
{
    static void Main(string[] args)
    {
        // Should pass
        TryComplex("(1.0,0.5)");
        TryComplex("(1.1+0.55i)");
        TryComplex(" ( 1.023 + 0.512 j ) ");
        TryComplex("(0, -1)");
        TryComplex("(0-1i)");
        TryComplex("(-10-2j)");
        TryComplex("(-10,-3)");
        TryComplex(" ( 1.8-1i ) ");
        TryComplex(" ( 1.9+1i ) ");

        // Culture specific
        TryComplex("(1,4, 2,5)");   // (14, 25) in UK (extra ','s ignored)

        // Should fail
        TryComplex(" ( 1,1i ) ");
        TryComplex("(1,4,2,5)");
        TryComplex(" ( 1.023 + 0.512 + j ) ");
        TryComplex(" ( 1.023, 0.512 j ) ");
        TryComplex(" ( 1.023i 0.512 j ) ");

        Console.ReadKey();  // Wait to close the console window
    }

    static void TryComplex(string text)
    {
        Console.Write($"Trying {text}: ");

        try
        {
            Complex result = text.ComplexParse();
            Console.WriteLine($"({result.Real}, {result.Imaginary})");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"*** Failed: {ex.Message} ***");
        }
    }
}

using System.Numerics;
using static ComplexParser.Complex2;    // Where ComplexParser is my outer namespace that contains the static class Complex2

TryComplex("(-8.98846567431158E+307, -8.98846567431158E+307)");

Trying (-8.98846567431158E+307, -8.98846567431158E+307): (-8.98846567431158E+307, -8.98846567431158E+307)
Trying (-8.98846567431158E+307,-8.98846567431158E+307): (-8.98846567431158E+307, -8.98846567431158E+307)
Trying (-8.98846567431158E+307+-8.98846567431158E+307i): *** Failed: Complex number format not recognised (multiple '+' chars) ***
Trying (-8.98846567431158E+307-8.98846567431158E+307i): *** Failed: Complex number format not recognised (multiple '+' chars) ***

Richard Deeming wrote:

And there's no actual reference to the nested Something1 class anywhere in that code.

Richard Deeming wrote:

You could remove that class, and the code would continue to run and function as expected.

BillWoodruff wrote:

Wrong.

Richard Deeming wrote:

The AddSomething and GetSomething methods depend on the interface, not the unused nested class.

Richard Deeming wrote:

prevent the user from creating new types that implement the interface outside of your assembly?

// in OuterClass1
internal T NewInstance<T>(params object[] args)
    where T : class, ISomething1
{
    var ttype = typeof(T);

    ISomething1 instance = null;

    instance = (T) Activator.CreateInstance(ttype, args);

    Somethings.Add(instance);

    return (T) instance;
}

Richard Deeming wrote:

If the collection class is public, then trying to further restrict the type ...

Richard Deeming wrote:

... to those in the current assembly, or an approved list of assemblies, is usually a sign of a broken design.