| `'b'` | Binary format. Outputs the number in base 2. Using the `'#'` option with this type adds the prefix `"0b"` to the output value. |
| `'B'` | Binary format. Outputs the number in base 2. Using the `'#'` option with this type adds the prefix `"0B"` to the output value. |
| `'c'` | Character format. Outputs the number as a character. |
| `'d'` | Decimal integer. Outputs the number in base 10. |
| `'o'` | Octal format. Outputs the number in base 8. |
| `'x'` | Hex format. Outputs the number in base 16, using lower-case letters for the digits above 9. Using the `'#'` option with this type adds the prefix `"0x"` to the output value. |
| `'X'` | Hex format. Outputs the number in base 16, using upper-case letters for the digits above 9. Using the `'#'` option with this type adds the prefix `"0X"` to the output value. |
| none | The same as `'d'`. |
Integer presentation types can also be used with character and Boolean values
with the only exception that `'c'` cannot be used with `bool`. Boolean values
are formatted using textual representation, either `true` or `false`, if the
presentation type is not specified.
The available presentation types for floating-point values are:
<tablestyle="width:96%;">
<colgroup>
<colstyle="width: 13%"/>
<colstyle="width: 81%"/>
</colgroup>
<thead>
<trclass="header">
<th>Type</th>
<th>Meaning</th>
</tr>
</thead>
<tbody>
<trclass="odd">
<td><code>'a'</code></td>
<td>Hexadecimal floating point format. Prints the number in base 16 with
prefix <code>"0x"</code> and lower-case letters for digits above 9. Uses
<code>'p'</code> to indicate the exponent.</td>
</tr>
<trclass="even">
<td><code>'A'</code></td>
<td>Same as <code>'a'</code> except it uses upper-case letters for the
prefix, digits above 9 and to indicate the exponent.</td>
</tr>
<trclass="odd">
<td><code>'e'</code></td>
<td>Exponent notation. Prints the number in scientific notation using
the letter 'e' to indicate the exponent.</td>
</tr>
<trclass="even">
<td><code>'E'</code></td>
<td>Exponent notation. Same as <code>'e'</code> except it uses an
upper-case <code>'E'</code> as the separator character.</td>
</tr>
<trclass="odd">
<td><code>'f'</code></td>
<td>Fixed point. Displays the number as a fixed-point number.</td>
</tr>
<trclass="even">
<td><code>'F'</code></td>
<td>Fixed point. Same as <code>'f'</code>, but converts <code>nan</code>
to <code>NAN</code> and <code>inf</code> to <code>INF</code>.</td>
</tr>
<trclass="odd">
<td><code>'g'</code></td>
<td><p>General format. For a given precision <code>p >= 1</code>,
this rounds the number to <code>p</code> significant digits and then
formats the result in either fixed-point format or in scientific
notation, depending on its magnitude.</p>
<p>A precision of <code>0</code> is treated as equivalent to a precision
of <code>1</code>.</p></td>
</tr>
<trclass="even">
<td><code>'G'</code></td>
<td>General format. Same as <code>'g'</code> except switches to
<code>'E'</code> if the number gets too large. The representations of
infinity and NaN are uppercased, too.</td>
</tr>
<trclass="odd">
<td>none</td>
<td>Similar to <code>'g'</code>, except that the default precision is as
high as needed to represent the particular value.</td>
</tr>
</tbody>
</table>
The available presentation types for pointers are:
| `'a'` | The abbreviated weekday name, e.g. "Sat". If the value does not contain a valid weekday, an exception of type `format_error` is thrown. |
| `'A'` | The full weekday name, e.g. "Saturday". If the value does not contain a valid weekday, an exception of type `format_error` is thrown. |
| `'b'` | The abbreviated month name, e.g. "Nov". If the value does not contain a valid month, an exception of type `format_error` is thrown. |
| `'B'` | The full month name, e.g. "November". If the value does not contain a valid month, an exception of type `format_error` is thrown. |
| `'c'` | The date and time representation, e.g. "Sat Nov 12 22:04:00 1955". The modified command `%Ec` produces the locale's alternate date and time representation. |
| `'C'` | The year divided by 100 using floored division, e.g. "19". If the result is a single decimal digit, it is prefixed with 0. The modified command `%EC` produces the locale's alternative representation of the century. |
| `'d'` | The day of month as a decimal number. If the result is a single decimal digit, it is prefixed with 0. The modified command `%Od` produces the locale's alternative representation. |
| `'D'` | Equivalent to `%m/%d/%y`, e.g. "11/12/55". |
| `'e'` | The day of month as a decimal number. If the result is a single decimal digit, it is prefixed with a space. The modified command `%Oe` produces the locale's alternative representation. |
| `'F'` | Equivalent to `%Y-%m-%d`, e.g. "1955-11-12". |
| `'g'` | The last two decimal digits of the ISO week-based year. If the result is a single digit it is prefixed by 0. |
| `'G'` | The ISO week-based year as a decimal number. If the result is less than four digits it is left-padded with 0 to four digits. |
| `'h'` | Equivalent to `%b`, e.g. "Nov". |
| `'H'` | The hour (24-hour clock) as a decimal number. If the result is a single digit, it is prefixed with 0. The modified command `%OH` produces the locale's alternative representation. |
| `'I'` | The hour (12-hour clock) as a decimal number. If the result is a single digit, it is prefixed with 0. The modified command `%OI` produces the locale's alternative representation. |
| `'j'` | If the type being formatted is a specialization of duration, the decimal number of days without padding. Otherwise, the day of the year as a decimal number. Jan 1 is 001. If the result is less than three digits, it is left-padded with 0 to three digits. |
| `'m'` | The month as a decimal number. Jan is 01. If the result is a single digit, it is prefixed with 0. The modified command `%Om` produces the locale's alternative representation. |
| `'M'` | The minute as a decimal number. If the result is a single digit, it is prefixed with 0. The modified command `%OM` produces the locale's alternative representation. |
| `'n'` | A new-line character. |
| `'p'` | The AM/PM designations associated with a 12-hour clock. |
| `'q'` | The duration's unit suffix. |
| `'Q'` | The duration's numeric value (as if extracted via `.count()`). |
| `'r'` | The 12-hour clock time, e.g. "10:04:00 PM". |
| `'R'` | Equivalent to `%H:%M`, e.g. "22:04". |
| `'S'` | Seconds as a decimal number. If the number of seconds is less than 10, the result is prefixed with 0. If the precision of the input cannot be exactly represented with seconds, then the format is a decimal floating-point number with a fixed format and a precision matching that of the precision of the input (or to a microseconds precision if the conversion to floating-point decimal seconds cannot be made within 18 fractional digits). The character for the decimal point is localized according to the locale. The modified command `%OS` produces the locale's alternative representation. |
| `'t'` | A horizontal-tab character. |
| `'T'` | Equivalent to `%H:%M:%S`. |
| `'u'` | The ISO weekday as a decimal number (1-7), where Monday is 1. The modified command `%Ou` produces the locale's alternative representation. |
| `'U'` | The week number of the year as a decimal number. The first Sunday of the year is the first day of week 01. Days of the same year prior to that are in week 00. If the result is a single digit, it is prefixed with 0. The modified command `%OU` produces the locale's alternative representation. |
| `'V'` | The ISO week-based week number as a decimal number. If the result is a single digit, it is prefixed with 0. The modified command `%OV` produces the locale's alternative representation. |
| `'w'` | The weekday as a decimal number (0-6), where Sunday is 0. The modified command `%Ow` produces the locale's alternative representation. |
| `'W'` | The week number of the year as a decimal number. The first Monday of the year is the first day of week 01. Days of the same year prior to that are in week 00. If the result is a single digit, it is prefixed with 0. The modified command `%OW` produces the locale's alternative representation. |
| `'x'` | The date representation, e.g. "11/12/55". The modified command `%Ex` produces the locale's alternate date representation. |
| `'X'` | The time representation, e.g. "10:04:00". The modified command `%EX` produces the locale's alternate time representation. |
| `'y'` | The last two decimal digits of the year. If the result is a single digit it is prefixed by 0. The modified command `%Oy` produces the locale's alternative representation. The modified command `%Ey` produces the locale's alternative representation of offset from `%EC` (year only). |
| `'Y'` | The year as a decimal number. If the result is less than four digits it is left-padded with 0 to four digits. The modified command `%EY` produces the locale's alternative full year representation. |
| `'z'` | The offset from UTC in the ISO 8601:2004 format. For example -0430 refers to 4 hours 30 minutes behind UTC. If the offset is zero, +0000 is used. The modified commands `%Ez` and `%Oz` insert a `:` between the hours and minutes: -04:30. If the offset information is not available, an exception of type `format_error` is thrown. |
| `'Z'` | The time zone abbreviation. If the time zone abbreviation is not available, an exception of type `format_error` is thrown. |
| `'%'` | A % character. |
Specifiers that have a calendaric component such as `'d'` (the day of
month) are valid only for `std::tm` and time points but not durations.
## Range Format Specifications
Format specifications for range types have the following syntax:
