std::countr_zero - cppreference.com (original) (raw)

| Defined in header | | | | ---------------------------------------------------------------- | | ------------- | | 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).

[edit] Parameters

[edit] Return value

The number of consecutive ​0​ bits in the value of x, starting from the least significant bit.

[edit] Notes

[edit] Example

#include #include #include #include   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

[edit] See also

| | counts the number of consecutive ​0​ bits, starting from the most significant bit (function template) [edit] | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | counts the number of consecutive 1 bits, starting from the most significant bit (function template) [edit] | | | counts the number of consecutive 1 bits, starting from the least significant bit (function template) [edit] | | | counts the number of 1 bits in an unsigned integer (function template) [edit] | | | checks if all, any or none of the bits are set to true (public member function of std::bitset) [edit] |