W3cubDocs

/C++

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

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