Question

How to get the bitwise left-rotation of X by N positions (left circular shift) using bitset in C++

Answer 1

#include <bitset>
#include <cstdint>
#include <iostream>
 
// C++ 20 (and above)
  
int main()
{
    // constexpr T rotl(T x, int s) noexcept;
     
    const std::uint8_t i = 0b01101110;
    std::cout << "i          = " << std::bitset<8>(i) << '\n';
    std::cout << "rotl(i, 0) = " << std::bitset<8>(std::rotl(i, 0)) << '\n';
    std::cout << "rotl(i, 1) = " << std::bitset<8>(std::rotl(i, 1)) << '\n';
    std::cout << "rotl(i, 2) = " << std::bitset<8>(std::rotl(i, 2)) << '\n';
    std::cout << "rotl(i, 4) = " << std::bitset<8>(std::rotl(i, 4)) << '\n';
}
 
 
/*
run:
 
i          = 01101110
rotl(i, 0) = 01101110
rotl(i, 1) = 11011100
rotl(i, 2) = 10111001
rotl(i, 4) = 11100110
 
*/

 

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