std::showpoint, std::noshowpoint

From cppreference.com
< cpp‎ | io‎ | manip
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

#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

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