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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