std::boolalpha, std::noboolalpha
From cppreference.com
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
Input/output library
Print functions (C++23)
Buffers
(C++23)
(C++98/26*)
(C++20)
Streams
Abstractions
File I/O
String I/O
Array I/O
(C++23)
(C++23)
(C++23)
(C++98/26*)
(C++98/26*)
(C++98/26*)
Synchronized Output
(C++20)
Types
Error category interface
(C++11)
(C++11)
Input/output manipulators
Floating-point formatting
(C++11)(C++11)
Integer formatting
Boolean formatting
boolalphanoboolalpha
Field width and fill control
Other formatting
Whitespace processing
Output flushing
(C++20)(C++20)
Status flags manipulation
Time and money I/O
Quoted manipulator
(C++14)
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 .
Contents
[edit] Parameters
str
-
reference to I/O stream
[edit] Return value
str (reference to the stream after manipulation).
[edit] 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
[edit] See also
[virtual]
(virtual protected member function of
std::numpunct<CharT>) [edit]