std::showpoint, std::noshowpoint

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Input/output library

I/O manipulators

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf (deprecated in C++98)

basic_syncbuf (C++20)

Streams

Abstractions

ios_base

basic_ios

basic_istream

basic_ostream

basic_iostream

File I/O

basic_ifstream

basic_ofstream

basic_fstream

String I/O

basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

istrstream (deprecated in C++98)

ostrstream (deprecated in C++98)

strstream (deprecated in C++98)

Synchronized Output

basic_osyncstream (C++20)

Types

streamoff

streamsize

fpos

Error category interface

iostream_category (C++11)

io_errc (C++11)

 

Input/output manipulators

Floating-point formatting
showpointnoshowpoint setprecision	fixedscientifichexfloatdefaultfloat (C++11)(C++11)
Integer formatting
setbase showbasenoshowbase	dechexoct
Boolean formatting
boolalphanoboolalpha
Field width and fill control
setfill setw	internalleftright
Other formatting
showposnoshowpos	uppercasenouppercase
Whitespace processing
ws ends	skipwsnoskipws
Output flushing
flush endl flush_emit (C++20)	unitbufnounitbuf emit_on_flushno_emit_on_flush (C++20)(C++20)
Status flags manipulation
resetiosflags	setiosflags
Time and money I/O
get_money (C++11) get_time (C++11)	put_money (C++11) put_time (C++11)
Quoted manipulator
quoted (C++14)

 

Defined in header <ios>
std::ios_base& showpoint( std::ios_base& str );	(1)
std::ios_base& noshowpoint( std::ios_base& str );	(2)

Enables or disables the unconditional inclusion of the decimal point character in floating-point output. Has no effect on input.

1) enables the showpoint flag in the stream str as if by calling str.setf(std::ios_base::showpoint)

2) disables the showpoint flag in the stream str as if by calling str.unsetf(std::ios_base::showpoint)

This is an I/O manipulator, it may be called with an expression such as out << std::showpoint for any out of type std::basic_ostream or with an expression such as in >> std::showpoint for any in of type std::basic_istream.

The character to use as decimal point character is determined by the numpunct facet of the locale imbued in the stream at the time of output, as described in std::num_put::put

Parameters

str

-

reference to I/O stream

Return value

str (reference to the stream after manipulation)

Example

Run this code

#include <iostream>
int main()
{
    std::cout << "1.0 with showpoint: " << std::showpoint << 1.0 << '\n'
              << "1.0 with noshowpoint: " << std::noshowpoint << 1.0 << '\n';
}

Output:

1.0 with showpoint: 1.00000
1.0 with noshowpoint: 1

See also

resetiosflags	clears the specified ios_base flags (function)
setiosflags	sets the specified ios_base flags (function)