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

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

[edit] Parameters

[edit] Return value

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

[edit] Notes

[edit] Example

#include #include #include #include   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

[edit] See also