std::countr_one
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countr_one
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Defined in header
<bit>
template< class T >
constexpr int countr_one( T x ) noexcept;
(since C++20)
constexpr int countr_one( T x ) noexcept;
Returns the number of consecutive 1 bits in the value of x, starting from the least significant bit ("right").
This overload participates in overload resolution only if T is an unsigned integer type (that is, unsigned char, unsigned short, unsigned int, unsigned long, unsigned long long, or an extended unsigned integer type).
Contents
[edit] Parameters
x
-
value of unsigned integer type
[edit] Return value
The number of consecutive 1 bits in the value of x, starting from the least significant bit.
[edit] Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_bitops |
201907L |
(C++20) | Bit operations |
[edit] Example
Run this code
#include <bit> #include <bitset> #include <cstdint> #include <iostream> int main() { for (const std::uint8_t i : {0, 0b11111111, 0b11111110, 0b11100011}) std::cout << "countr_one( " << std::bitset <8>(i) << " ) = " << std::countr_one(i) << '\n'; }
Output:
countr_one( 00000000 ) = 0 countr_one( 11111111 ) = 8 countr_one( 11111110 ) = 0 countr_one( 11100011 ) = 2
[edit] See also
(C++20)
(function template) [edit]
(C++20)
(function template) [edit]
(C++20)
(function template) [edit]
checks if all, any or none of the bits are set to true
(public member function of
(public member function of
std::bitset<N>) [edit]