std::countl_one
Defined in header <bit> |
||
---|---|---|
template< class T > constexpr int countl_one( T x ) noexcept; |
(since C++20) |
Returns the number of consecutive 1 ("one") bits in the value of x
, starting from the most significant bit ("left").
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 most 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, 0b01111111, 0b11100011 }) { std::cout << "countl_one( " << std::bitset<8>(i) << " ) = " << std::countl_one(i) << '\n'; } }
Output:
countl_one( 00000000 ) = 0 countl_one( 11111111 ) = 8 countl_one( 01111111 ) = 0 countl_one( 11100011 ) = 3
See also
(C++20)
|
counts the number of consecutive 0 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 consecutive 1 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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