# <iomanip>
<iomanip>
# ``
* * *
Include the [iostreams](https://docs.qualcomm.com/doc/80-N3040-23/topic/cpp_lib_cpp.html#iostreams)
standard header **``**
to define several [manipulators](https://docs.qualcomm.com/doc/80-N3040-23/topic/cpp_ios.html#manipulators)
that each take a single argument. Each of these manipulators returns
an unspecified type, called `T1` through `T6`
here, that overloads both
`basic_istream::operator>>`
and
`basic_ostream::operator<<`.
Thus, you can write extractors and inserters such as:
cin >> setbase(8);
cout << setbase(8);Copy to clipboard
namespace std {
T1 resetiosflags(ios_base::fmtflags mask);
T2 setiosflags(ios_base::fmtflags mask);
T3 setbase(int base);
template
T4 setfill(Elem ch);
T5 setprecision(streamsize prec);
T6 setw(streamsize wide);
} // namespace stdCopy to clipboard
## `resetiosflags`
T1 resetiosflags(ios_base::fmtflags mask);Copy to clipboard
The manipulator returns an object that, when extracted from or
inserted into the stream `str`, calls
`str.setf(ios_base::
fmtflags(), mask)`,
then returns `str`.
## `setbase`
T3 setbase(int base);Copy to clipboard
The manipulator returns an object that, when extracted from or
inserted into the stream `str`, calls
`str.setf(mask,
ios_base::basefield)`,
then returns `str`. Here, `mask` is determined
as follows:
- If `base` is 8, then `mask` is
`ios_base::oct`
- If `base` is 10, then `mask` is
`ios_base::dec`
- If `base` is 16, then `mask` is
`ios_base::hex`
- If `base` is any other value, then `mask` is
`ios_base::fmtflags(0)`
## `setfill`
template
T4 setfill(Elem ch);Copy to clipboard
The template manipulator returns an object that, when extracted from or
inserted into the stream `str`, calls
`str.fill(ch)`,
then returns `str`. The type `Elem` must be the
same as the element type for the stream `str`.
## `setiosflags`
T2 setiosflags(ios_base::fmtflags mask);Copy to clipboard
The manipulator returns an object that, when extracted from or
inserted into the stream `str`, calls
`str.setf(mask)`,
then returns `str`.
## `setprecision`
T5 setprecision(streamsize prec);Copy to clipboard
The manipulator returns an object that, when extracted from or
inserted into the stream `str`, calls
`str.precision(prec)`,
then returns `str`.
## `setw`
T6 setw(streamsize wide);Copy to clipboard
The manipulator returns an object that, when extracted from or
inserted into the stream `str`, calls
`str.width(wide)`,
then returns `str`.
* * *
See also the
**[Table of Contents](https://docs.qualcomm.com/doc/80-N3040-23/topic/cpp_index.html#Table%20of%20Contents)** and the
**[Index](https://docs.qualcomm.com/doc/80-N3040-23/topic/_cpp_index.html)**.
*[Copyright](https://docs.qualcomm.com/doc/80-N3040-23/topic/cpp_crit_pjp.html) © 1992-2006by P.J. Plauger. All rights reserved.*
Last Published: Oct 06, 2026
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