Format double type with minimum number of decimal digits

Question

I need to format double type so that it has minimum two decimal digits but without limitation for maximum number of decimal digits:

5     -> "5.00"
5.5   -> "5.50"
5.55  -> "5.55"
5.555 -> "5.555"
5.5555 -> "5.5555"

How can I achieve it?

Answer 1

You can use the 0 format specificer for non-optional digits, and # for optional digits:

n.ToString("0.00###")

This example gives you up to five decimal digits, you can add more # positions as needed.

Answer 2

Try this

    static void Main(string[] args)
    {
        Console.WriteLine(FormatDecimal(1.678M));
        Console.WriteLine(FormatDecimal(1.6M));
        Console.ReadLine();

    }

    private static string FormatDecimal(decimal input)
    {
        return Math.Abs(input - decimal.Parse(string.Format("{0:0.00}", input))) > 0 ?
            input.ToString() :
            string.Format("{0:0.00}", input);
    }