The format string consists of zero or more conversion specifiers and ordinary characters (except %
). All ordinary characters, including the terminating null character, are copied to the output string without modification. Each conversion specification begins with %
character, optionally followed by E
or O
modifier (ignored if unsupported by the locale), followed by the character that determines the behavior of the specifier. The following format specifiers are available:
Conversion specifier | Explanation | Used fields |
% | writes literal % . The full conversion specification must be %% . | |
n (C++11) | writes newline character | |
t (C++11) | writes horizontal tab character | |
Year |
Y | writes year as a decimal number, e.g. 2017 | tm_year |
EY (C++11) | writes year in the alternative representation, e.g.平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | tm_year |
y | writes last 2 digits of year as a decimal number (range [00,99] ) | tm_year |
Oy (C++11) | writes last 2 digits of year using the alternative numeric system, e.g. 十一 instead of 11 in ja_JP locale | tm_year |
Ey (C++11) | writes year as offset from locale's alternative calendar period %EC (locale-dependent) | tm_year |
C (C++11) | writes first 2 digits of year as a decimal number (range [00,99] ) | tm_year |
EC (C++11) | writes name of the base year (period) in the locale's alternative representation, e.g. 平成 (Heisei era) in ja_JP | tm_year |
G (C++11) | writes ISO 8601 week-based year, i.e. the year that contains the specified week. In IS0 8601 weeks begin with Monday and the first week of the year must satisfy the following requirements:
- Includes January 4
- Includes first Thursday of the year
| tm_year , tm_wday , tm_yday |
g (C++11) | writes last 2 digits of ISO 8601 week-based year, i.e. the year that contains the specified week (range [00,99] ). In IS0 8601 weeks begin with Monday and the first week of the year must satisfy the following requirements:
- Includes January 4
- Includes first Thursday of the year
| tm_year , tm_wday , tm_yday |
Month |
b | writes abbreviated month name, e.g. Oct (locale dependent) | tm_mon |
h (C++11) | synonym of b | tm_mon |
B | writes full month name, e.g. October (locale dependent) | tm_mon |
m | writes month as a decimal number (range [01,12] ) | tm_mon |
Om (C++11) | writes month using the alternative numeric system, e.g. 十二 instead of 12 in ja_JP locale | tm_mon |
Week |
U | writes week of the year as a decimal number (Sunday is the first day of the week) (range [00,53] ) | tm_year , tm_wday , tm_yday |
OU (C++11) | writes week of the year, as by %U , using the alternative numeric system, e.g. 五十二 instead of 52 in ja_JP locale | tm_year , tm_wday , tm_yday |
W | writes week of the year as a decimal number (Monday is the first day of the week) (range [00,53] ) | tm_year , tm_wday , tm_yday |
OW (C++11) | writes week of the year, as by %W , using the alternative numeric system, e.g. 五十二 instead of 52 in ja_JP locale | tm_year , tm_wday , tm_yday |
V (C++11) | writes ISO 8601 week of the year (range [01,53] ). In IS0 8601 weeks begin with Monday and the first week of the year must satisfy the following requirements:
- Includes January 4
- Includes first Thursday of the year
| tm_year , tm_wday , tm_yday |
OV (C++11) | writes week of the year, as by %V , using the alternative numeric system, e.g. 五十二 instead of 52 in ja_JP locale | tm_year , tm_wday , tm_yday |
Day of the year/month |
j | writes day of the year as a decimal number (range [001,366] ) | tm_yday |
d | writes day of the month as a decimal number (range [01,31] ) | tm_mday |
Od (C++11) | writes zero-based day of the month using the alternative numeric system, e.g 二十七 instead of 27 in ja_JP locale Single character is preceded by a space.
| tm_mday |
e (C++11) | writes day of the month as a decimal number (range [1,31] ). Single digit is preceded by a space.
| tm_mday |
Oe (C++11) | writes one-based day of the month using the alternative numeric system, e.g. 二十七 instead of 27 in ja_JP locale Single character is preceded by a space.
| tm_mday |
Day of the week |
a | writes abbreviated weekday name, e.g. Fri (locale dependent) | tm_wday |
A | writes full weekday name, e.g. Friday (locale dependent) | tm_wday |
w | writes weekday as a decimal number, where Sunday is 0 (range [0-6] ) | tm_wday |
Ow (C++11) | writes weekday, where Sunday is 0 , using the alternative numeric system, e.g. 二 instead of 2 in ja_JP locale | tm_wday |
u (C++11) | writes weekday as a decimal number, where Monday is 1 (ISO 8601 format) (range [1-7] ) | tm_wday |
Ou (C++11) | writes weekday, where Monday is 1 , using the alternative numeric system, e.g. 二 instead of 2 in ja_JP locale | tm_wday |
Hour, minute, second |
H | writes hour as a decimal number, 24 hour clock (range [00-23] ) | tm_hour |
OH (C++11) | writes hour from 24-hour clock using the alternative numeric system, e.g. 十八 instead of 18 in ja_JP locale | tm_hour |
I | writes hour as a decimal number, 12 hour clock (range [01,12] ) | tm_hour |
OI (C++11) | writes hour from 12-hour clock using the alternative numeric system, e.g. 六 instead of 06 in ja_JP locale | tm_hour |
M | writes minute as a decimal number (range [00,59] ) | tm_min |
OM (C++11) | writes minute using the alternative numeric system, e.g. 二十五 instead of 25 in ja_JP locale | tm_min |
S | writes second as a decimal number (range [00,60] ) | tm_sec |
OS (C++11) | writes second using the alternative numeric system, e.g. 二十四 instead of 24 in ja_JP locale | tm_sec |
Other |
c | writes standard date and time string, e.g. Sun Oct 17 04:41:13 2010 (locale dependent) | all |
Ec (C++11) | writes alternative date and time string, e.g. using 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | all |
x | writes localized date representation (locale dependent) | all |
Ex (C++11) | writes alternative date representation, e.g. using 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | all |
X | writes localized time representation (locale dependent) | all |
EX (C++11) | writes alternative time representation (locale dependent) | all |
D (C++11) | equivalent to "%m/%d/%y" | tm_mon , tm_mday , tm_year |
F (C++11) | equivalent to "%Y-%m-%d" (the ISO 8601 date format) | tm_mon , tm_mday , tm_year |
r (C++11) | writes localized 12-hour clock time (locale dependent) | tm_hour , tm_min , tm_sec |
R (C++11) | equivalent to "%H:%M" | tm_hour , tm_min |
T (C++11) | equivalent to "%H:%M:%S" (the ISO 8601 time format) | tm_hour , tm_min , tm_sec |
p | writes localized a.m. or p.m. (locale dependent) | tm_hour |
z (C++11) | writes offset from UTC in the ISO 8601 format (e.g. -0430 ), or no characters if the time zone information is not available | tm_isdst |
Z | writes locale-dependent time zone name or abbreviation, or no characters if the time zone information is not available | tm_isdst |