Defined in header <bit> | ||
---|---|---|
template< class T > constexpr int countl_zero( T x ) noexcept; | (since C++20) |
Returns the number of consecutive 0 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).
x | - | value of unsigned integer type |
The number of consecutive 0 bits in the value of x
, starting from the most significant bit.
Feature-test macro | Value | Std | Comment |
---|---|---|---|
__cpp_lib_bitops | 201907L | (C++20) | Bit operations |
#include <bit> #include <bitset> #include <cstdint> #include <iostream> int main() { for (const std::uint8_t i : {0, 0b11111111, 0b11110000, 0b00011110}) std::cout << "countl_zero( " << std::bitset<8>(i) << " ) = " << std::countl_zero(i) << '\n'; }
Output:
countl_zero( 00000000 ) = 8 countl_zero( 11111111 ) = 0 countl_zero( 11110000 ) = 0 countl_zero( 00011110 ) = 3
(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 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) |
checks if all, any or none of the bits are set to true (public member function of std::bitset<N> ) |
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