Csharp/C Sharp by API/System/IFormattable

implements IFormattable

 

using System;
using System.Globalization;
public sealed class ComplexNumber : IFormattable
{
    public ComplexNumber( double real, double imaginary ) {
        this.real = real;
        this.imaginary = imaginary;
    }
    public override string ToString() {
        return ToString( "G", null );
    }
    public string ToString( string format, IFormatProvider formatProvider ) {
        string result = "(" + real.ToString(format, formatProvider) + " " + real.ToString(format, formatProvider) + ")";
        return result;
    }
   
    private readonly double real;
    private readonly double imaginary;
}
public sealed class MainClass
{
    static void Main() {
        ComplexNumber num1 = new ComplexNumber( 1.12345678, 2.12345678 );
        
        Console.WriteLine( "US format: {0}", num1.ToString( "F5", new CultureInfo("en-US") ) );
        Console.WriteLine( "DE format: {0}", num1.ToString( "F5", new CultureInfo("de-DE") ) );
        Console.WriteLine( "Object.ToString(): {0}",num1.ToString() );
    }
}