Difference between revisions of "cpp/numeric/countr zero"
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===Return value=== | ===Return value=== | ||
The number of consecutive 0 bits in the value of {{tt|x}}, starting from the least significant bit. | The number of consecutive 0 bits in the value of {{tt|x}}, starting from the least significant bit. | ||
| + | |||
| + | ===Notes=== | ||
| + | {{feature test macro|__cpp_lib_bitops}} | ||
=== Example === | === Example === | ||
Revision as of 14:52, 31 January 2022
| Defined in header <bit>
|
||
| template< class T > constexpr int countr_zero( T x ) noexcept; |
(since C++20) | |
Returns the number of consecutive 0 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 |
Parameters
| x | - | values of unsigned integer type |
Return value
The number of consecutive 0 bits in the value of x, starting from the least significant bit.
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_bitops |
Example
Run this code
#include <bit> #include <bitset> #include <cstdint> #include <iostream> int main() { for (const std::uint8_t i : { 0, 0b11111111, 0b00011100, 0b00011101 }) { std::cout << "countr_zero( " << std::bitset<8>(i) << " ) = " << std::countr_zero(i) << '\n'; } }
Output:
countr_zero( 00000000 ) = 8 countr_zero( 11111111 ) = 0 countr_zero( 00011100 ) = 2 countr_zero( 00011101 ) = 0
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 1 bits, starting from the most 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>)
|
