From cppreference.com
Defined in header
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
or with an expression such as in>>std::boolalpha for any in of type
.
Parameters
str - reference to I/O stream Return value
str (reference to the stream after manipulation).
Example
Run this code
#include<iostream>#include<sstream>intmain(){// boolalpha outputstd::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 parseboolb1,b2;std::istringstreamis("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