From cppreference.com
Defined in header
template<classT>constexprintcountr_zero(Tx)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, unsignedchar, unsignedshort, unsignedint, unsignedlong, unsignedlonglong, or an extended unsigned integer type).
Parameters
x - value of unsigned integer type Return value
The number of consecutive 0 bits in the value of x, starting from the least significant bit.
Notes
macroValueStdFeature
(C++20)
Example
Run this code
#include<bit>#include<bitset>#include<cstdint>#include<iostream>intmain(){for(conststd::uint8_ti:{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>)