c＃将String转换为双精度损失

Question

I have the following:

string value = "9223372036854775807";
double parsedVal = double.Parse(value, CultureInfo.InvariantCulture);

... and the result is 9.2233720368547758E+18 which is not the exact same number. How should I convert string to double without loss of precision?

Answer 1

double can only guarantee 16 (approx) decimal digits of accuracy. You might try switching to decimal (which has a few more bits to play with, and holds that value with plenty of headroom).

Answer 2

You can't convert 9223372036854775807 to double without loss of precision, due to the definition of a double (( IEEE 754 ) standard for binary floating-point arithmetic).

By default, a Double value contains 15 decimal digits of precision, although a maximum of 17 digits is maintained internally.

Answer 3

Using Decimal will get you the precision you need here. However please note that Decimal will not have the same storage range as a double.

See Can C# store more precise data than doubles?