std::countr_one
Defined in header <bit> |
||
|---|---|---|
template< class T > constexpr int countr_one( T x ) noexcept; |
(since C++20) |
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).
Parameters
| x | - | value of unsigned integer type |
Return value
The number of consecutive 1 bits in the value of x, starting from the least significant bit.
Notes
Feature testing macro: __cpp_lib_bitops.
Example
#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
See also
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(C++20)
|
counts the number of consecutive 0 bits, starting from the most significant bit (function template) |
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(C++20)
|
counts the number of consecutive 1 bits, starting from the most significant bit (function template) |
|
(C++20)
|
counts the number of consecutive 0 bits, starting from the least significant bit (function template) |
|
(C++20)
|
counts the number of 1 bits in an unsigned integer (function template) |
|
(C++20)
|
checks if a number is an integral power of two (function template) |
returns the number of bits set to true (public member function of std::bitset<N>) |
|
|
(C++11)
|
checks if all, any or none of the bits are set to true (public member function of std::bitset<N>) |
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