About: Round-Trip Formatting，I can't understand！！

[BigFish3710]

I tried running this code：

Listing 2.9: Formatting Using the R Format Specifier
// ...
const double number = 1.618033988749895;
double result;
string text;

text = $"{number}";
result = double.Parse(text);
Console.WriteLine($"{result == number}: {result} == {number}");

text = $"{number:R}";
result = double.Parse(text);
Console.WriteLine($"{result == number}: {result} == {number}");

// ...

The result is:
True: result == number
True: result == number
True: 1.618033988749895 == 1.618033988749895
True: 1.618033988749895 == 1.618033988749895

This result is not the same as prefetching, and I can't understand such a result.

[BenjaminMichaelis]

Hi @BigFish3710; Thanks for opening a discussion on this; there are two issues here:

1. There is a bug in the output; I am working on fixing this in the text and will push updates to the website; it should not just show "result == number"
2. The behavior of round-trip format has changed; I am looking into this but wanted to make sure you were being kept up to date. (The change was likely caused by Update the double/float formatters to return the shortest roundtrippable string. dotnet/coreclr#22040 if interested).

[BigFish3710]

Thank you! For me as a beginner, I can only understand this problem now!!!