std::bitset<N>::set

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (C++20) Dynamic memory management Program utilities Coroutine support (C++20) Variadic functions is_constant_evaluated (C++20) is_within_lifetime (C++26) initializer_list (C++11) source_location (C++20) Three-way comparison three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20)   is_eqis_ltis_lteq (C++20)(C++20)(C++20)   is_neqis_gtis_gteq (C++20)(C++20)(C++20)

General utilities Date and time Function objects Formatting library (C++20)   bitset hash (C++11) Relational operators (deprecated in C++20) rel_ops::operator!=rel_ops::operator>    rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (C++20)(C++20)(C++20)   cmp_not_equalcmp_greatercmp_greater_than (C++20)(C++20)(C++20) in_range (C++20) Swap and type operations swap ranges::swap (C++20) exchange (C++14) declval (C++11) to_underlying (C++23) forward (C++11) forward_like (C++23) move (C++11) move_if_noexcept (C++11) as_const (C++17) Common vocabulary types pair tuple (C++11) optional (C++17) any (C++17) variant (C++17) tuple_size (C++11) tuple_element (C++11) apply (C++17) make_from_tuple (C++17) expected (C++23) Elementary string conversions to_chars (C++17) from_chars (C++17) chars_format (C++17) to_chars_result (C++17) from_chars_result (C++17)

 

std::bitset

Member types
bitset::reference
Member functions
bitset::bitset
bitset::operator==bitset::operator!= (until C++20)
Element access
bitset::operator[]
bitset::test
bitset::allbitset::anybitset::none (C++11)
bitset::count
Capacity
bitset::size
Modifiers
bitset::operator&=bitset::operator|=bitset::operator^=bitset::operator~
bitset::operator<<=bitset::operator>>=bitset::operator<<bitset::operator>>
bitset::set
bitset::reset
bitset::flip
Conversions
bitset::to_string
bitset::to_ulong
bitset::to_ullong (C++11)
Non-member functions
operator&operator|operator^	operator<<operator>>
Helper classes
std::hash (C++11)

 

bitset& set();	(1)	(noexcept since C++11) (constexpr since C++23)
bitset& set( std::size_t pos, bool value = true );	(2)	(constexpr since C++23)

Sets all bits to true or sets one bit to specified value.

1) Sets all bits to true.

2) Sets the bit at position pos to the value value.

Parameters

pos	-	the position (counting from ​0​, i.e. from least significant to most significant) of the bit to set
value	-	the value to set the bit to

Return value

*this

Exceptions

2) Throws std::out_of_range if pos does not correspond to a valid position within the bitset.

Example

Run this code

#include <bitset>
#include <cstddef>
#include <iostream>
 
int main()
{
    std::bitset<8> b;
    std::cout << b << '\n';
    std::cout << b.set() << '\n';
    std::cout << b.reset() << '\n';
 
    for (std::size_t i = 1; i < b.size(); i += 2)
        b.set(i);
 
    std::cout << b << '\n';
}

Output:

00000000
11111111
00000000
10101010

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 186	C++98	the type of value was int	corrected to bool

See also

reset	sets bits to false (public member function)
flip	toggles the values of bits (public member function)