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std::bitset<N>::to_string

(1)
template<
    class CharT,
    class Traits,
    class Allocator
>
std::basic_string<CharT, Traits, Allocator>
    to_string( CharT zero = CharT('0'), CharT one = CharT('1') ) const;
(until C++11)
template<
    class CharT = char,
    class Traits = std::char_traits<CharT>,
    class Allocator = std::allocator<CharT>
>
std::basic_string<CharT, Traits, Allocator>
    to_string( CharT zero = CharT('0'), CharT one = CharT('1') ) const;
(since C++11)
(constexpr since C++23)
template< class CharT, class Traits >
std::basic_string<CharT, Traits>
    to_string( CharT zero = CharT('0'), CharT one = CharT('1') ) const;
(2) (until C++11)
template< class CharT >
std::basic_string<CharT>
    to_string( CharT zero = CharT('0'), CharT one = CharT('1') ) const;
(3) (until C++11)
std::string to_string( char zero = '0', char one = '1' ) const;
(4) (until C++11)

Converts the contents of the bitset to a string. Uses zero to represent bits with value of false and one to represent bits with value of true.

The resulting string contains N characters with the first character corresponds to the last (N-1th) bit and the last character corresponding to the first bit.

All template type arguments need to be provided because function templates cannot have default template arguments. Overloads (2-4) are provided to simplify the invocations of to_string:

2) Uses the default allocator std::allocator. 3) Uses the default character trait std::char_traits and the default allocator std::allocator.
char
(until C++11)

Parameters

zero - character to use to represent false
one - character to use to represent true

Return value

1) The converted string.
2) to_string<CharT, Traits, std::allocator<CharT>>(zero, one).
3) to_string<CharT, std::char_traits<CharT>, std::allocator<CharT>>(zero, one).
4) to_string<char, std::char_traits<char>, std::allocator<char>>(zero, one).

Exceptions

May throw std::bad_alloc from the std::string constructor.

Notes

Since C++11, functions templates can have default template arguments. LWG issue 1113 removed the helper overloads (2-4) and added the corresponding default template arguments in (1).

Example

#include <iostream>
#include <bitset>
 
int main()
{
    std::bitset<8> b{42};
    std::cout << b.to_string() << '\n'
              << b.to_string('*') << '\n'
              << b.to_string('O', 'X') << '\n';
}

Output:

00101010
**1*1*1*
OOXOXOXO

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 396 C++98 zero and one bits were converted to characters ​0
and 1 (which do not correspond to '0' and '1')
added parameters to provide
values for these characters
LWG 434 C++98 all template arguments needed to be provided added overloads (2-4)
LWG 853 C++98 overloads (2-4) did not have the default
arguments added by LWG issue 396
also added

See also

returns an unsigned long integer representation of the data
(public member function)
(C++11)
returns an unsigned long long integer representation of the data
(public member function)

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