NAME¶

std::boolalpha,std::noboolalpha - std::boolalpha,std::noboolalpha

Synopsis¶

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

1) Enables the boolalpha flag in the stream str as if by calling
str.setf(std::ios_base::boolalpha).
2) Disables the boolalpha flag in the stream str as if by calling
str.unsetf(std::ios_base::boolalpha).

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

Parameters¶

str - reference to I/O stream

Return value¶

str (reference to the stream after manipulation).

Example¶

// Run this code

#include <iostream>
#include <sstream>

int main()
{
// boolalpha output
std::cout << "default true: " << true << '\n'
<< "default false: " << false << '\n'
<< std::boolalpha
<< "boolalpha true: " << true << '\n'
<< "boolalpha false: " << false << '\n'
<< std::noboolalpha
<< "noboolalpha true: " << true << '\n'
<< "noboolalpha false: " << false << '\n';

// boolalpha parse
bool b1, b2;
std::istringstream is("true false");
is >> std::boolalpha >> b1 >> b2;

std::cout << '"' << is.str() << "\" parsed as: "
<< std::boolalpha << b1 << ' ' << b2 << '\n';
}

Output:¶

default true: 1
default false: 0
boolalpha true: true
boolalpha false: false
noboolalpha true: 1
noboolalpha false: 0
"true false" parsed as: true false

See also¶

resetiosflags clears the specified ios_base flags
(function)
setiosflags sets the specified ios_base flags
(function)
do_truename provides the string to use as the name of the boolean true and false
do_falsename (virtual protected member function of std::numpunct<CharT>)
[virtual]