c ++格式化具有自动精度的浮点数

Question

Is there a standard way of formatting a float (or double) in C++ in decimal with exactly enough precision to parse it back to the same bits?

That is, I want 1.F to be "1.0" and 2.002f to be "2.002" .

For cases, where decimal is inexact another format would be acceptable (scientific or even hex float). Does such a case exist?

All I can find is reference to std::fixed and std::setprecision such as this link . The precision is fixed for these.

Thanks.

Answer 1

I have to do exactly that a lot, ie, what you are trying to do. My solution is to use something like this:

char buf[32];
sprintf(buf, "%.15f", v);
TrimTrailingZeros(buf);