std::numpunct<CharT>::truename, do_truename, falsename, do_falsename

Defined in header `<locale>`
public: string_type truename() const;	(1)
public: string_type falsename() const;	(2)
protected: virtual string_type do_truename() const;	(3)
protected: virtual string_type do_falsename() const;	(4)

1-2) Public member function, calls the member function do_truename and do_falsename of the most derived class respectively.

3) Returns the string to be used as the representation of the boolean value true.

4) Returns the string to be used as the representation of the boolean value false.

Return value

1,3) The object of type string_type to use as the representation of true. The standard specializations of std::numpunct return "true" and L"true".

2,4) The object of type string_type to use as the representation of false. The standard specializations of std::numpunct return "false" and L"false".

Example

Run this code

#include <iostream>
#include <locale>
#include <iomanip>
 
struct custom_tf : std::numpunct<char> {
    std::string do_truename()  const { return "t"; }
    std::string do_falsename() const { return "f"; }
};
 
int main()
{
    std::cout << std::boolalpha;
    std::cout << "default locale: " << true << true << false << false << '\n';
    std::cout.imbue(std::locale(std::cout.getloc(), new custom_tf));
    std::cout << "locale with modified numpunct: " 
              << true << true << false << false << '\n';
}

Output:

default locale: truetruefalsefalse
locale with modified numpunct: ttff

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

Member functions
numpunct::numpunct
numpunct::~numpunct
numpunct::decimal_pointnumpunct::do_decimal_point
numpunct::thousands_sepnumpunct::do_thousands_sep
numpunct::groupingnumpunct::do_grouping
numpunct::truenamenumpunct::do_truenamenumpunct::falsenamenumpunct::do_falsename