CODEWITHSUNDEEP
c#c#-4.0
keerthee
keerthee

Reputation: 880

doublevalue.ToString() loses decimal places in C#

The ToString() of a double value, causes losing of the decimal places

(1521.6666666666667).ToString()   ==>  "1521.66666666667"

Is there any way to save all the decimal places when converting to string

Also 

(1521.6666666666667).ToString("F13");   => "1521.6666666666700"
(1521.6666666666667).ToString("0.0000000000000");   => "1521.6666666666700

Does this have to do with size of the double value

Upvotes: 4

Views: 2013

Answers (5)

SᴇM
SᴇM

Reputation: 7213

Use The Round-trip ("R") Format Specifier, which will attempts to ensure that a numeric value that is converted to a string is parsed back into the same numeric value. This format is supported only for the Single, Double, and BigInteger types.

But for Double and Single values, the "R" format specifier in some cases fails to successfully round-trip the original value and also offers relatively poor performance. Instead, we recommend that you use the "G17" format specifier for Double values and the "G9" format specifier to successfully round-trip Single values.

From MSDN:

In some cases, Double values formatted with the "R" standard numeric format string do not successfully round-trip if compiled using the /platform:x64 or /platform:anycpu switches and run on 64-bit systems.

Resource: Standard Numeric Format Strings.

Upvotes: 1

Jude
Jude

Reputation: 543

You have to format the string.

(1521.6666666666667).ToString("R");

Upvotes: 4

devuxer
devuxer

Reputation: 42354

decimal d = 1521.6666666666667M;
d.ToString();

According to the documentation:

Compared to floating-point types, the decimal type has more precision and a smaller range.

Specifically, decimal has 28-29 significant digits, rather than 15-16 for double.

Upvotes: 2

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186668

You can use Decimal instead of Double:

  (1521.6666666666667M).ToString(); // note "M"

Another possibility (if you have to use Double) is "R" format:

 (1521.6666666666667).ToString("R");

Upvotes: 1

TomTom
TomTom

Reputation: 62093

The solution to this is reading the documentation. Seriously It is NOT "ToString" that is loosing it.

Let me quote the float data Type from https://msdn.microsoft.com/en-us/library/b1e65aza.aspx:

Precision: 7 digits.

The numbers are in your source, they are never in the float. Not properly. The value is rounded.

Upvotes: 4

Related Questions