std::rotl

template< class T >
constexpr T rotl( T x, int s ) noexcept;

Computes the result of bitwise left-rotating the value of x by s positions. This operation is also known as a left circular shift.

Formally, let N be std::numeric_limits<T>::digits and r be s % N.

• If r is 0, returns x;
• if r is positive, returns (x << r) | (x >> (N - r));
• if r is negative, returns std::rotr(x, -r).

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

Return value

The result of bitwise left-rotating x by s positions.

Notes

Example

#include <bit>
#include <bitset>
#include <cstdint>
#include <iostream>

int main()
{
    using bin = std::bitset<8>;
    const std::uint8_t x{0b00011101};
    std::cout << bin(x) << " <- x\n";
    for (const int s : {0, 1, 4, 9, -1})
        std::cout << bin(std::rotl(x, s)) << " <- rotl(x, " << s << ")\n";
}

00011101 <- x
00011101 <- rotl(x, 0)
00111010 <- rotl(x, 1)
11010001 <- rotl(x, 4)
00111010 <- rotl(x, 9)
10001110 <- rotl(x, -1)

See also