Produce a round-trip string for a decimal type

Question

If I wanted to convert a double to a string and back to a double that matches exactly, I would use something like:

double d1 = 1 / 3.0;
string s = d1.ToString("R");
double d2 = double.Parse(s);

But, the "R" format isn't defined for a decimal type (you get a "FormatException: Format specifier was invalid").

What is the way to produce a round-trip string for a decimal type?

Answer 1

The default output format for decimal round-trips, so you don't have to do anything special. It is just like int in that sense.

Answer 2

Decimal is in fact a binary-decimal value (it uses base of 10 , not 2 as in Double ) and that's why there's no need to special exact representations like ToString("R") ;

  Decimal value = 123.456m;
  String result = value.ToString(CultureInfo.InvariantCulture); // <- That's enough 

See also for details:

http://csharpindepth.com/articles/general/decimal.aspx

Answer 3

If you try,

decimal d1 = 1m / 3;
string s = d1.ToString();
decimal d2 = decimal.Parse(s);
// where d1 == d2 = true

You will see you do not need any extra formatting options to obtain a proper string representation.