class MyNumber : IFormattable
{
decimal value;
public MyNumber(decimal value)
{ this.value = value; }
string IFormattable.ToString(string format, IFormatProvider formatProvider)
{ return value.ToString(format, formatProvider); }
public string ToString(string format)
{ return ((IFormattable)this).ToString(format, System.Globalization.CultureInfo.CurrentCulture); }
}
class Program
{
static void Main(string[] args)
{
MyNumber num = new MyNumber(3.1415926m);
Console.WriteLine(num.ToString("0.0000"));
Console.WriteLine("{0:0.0000}", num);
}
}