chars_format enum

Used with the <charconv> library to specify the floating-point format for primitive numerical conversions.

Syntax

enum class chars_format {
    scientific = unspecified,
    fixed = unspecified,
    hex = unspecified,
    general = fixed | scientific
};

Members

Element	Description
scientific	Causes from_chars() to expect and parse an exponent. It is like the printf() format specifier 'e', which formats for scientific notation, like "1.729e+01".
fixed	Causes from_chars() not to expect or parse an exponent. It is like the printf() format specifier 'f', which formats for floating-point, like "17.29".
hex	Causes from_chars() to expect the number in hexadecimal format, but without a leading 0x.
general	Causes from_chars() to accept (but not require) an exponent. For to_chars(), it is like the printf() format specifier 'g', which switches between scientific notation or fixed. It takes into consideration what the exponent will be so that it can generate reasonably compact output. For example: 1e-5 results in "1e-05", but 1e-4 results in "0.001". 1e5 results in 100000, while 1e6 results in 1e+06. 1e0 produces 1.

Remarks

For the from_chars functions, this enum describes what kind of input to expect. For the to_chars functions, it describes what kind of output to emit.

Requirements

Header: <charconv>

Namespace: std

/std:c++17 or later is required.

See also

<charconv>
printf() format specifiers