Rotate Left in an 8-bit Register

Code

#include <stdio.h>
#include <stdint.h>

uint8_t rotate_left(uint8_t reg, uint8_t n) {
   n = n % 8;
   return ((reg << n) | (reg >> (8 - n))) & 0xFF;
}

int main() {
    uint8_t reg, n;
    scanf("%hhu %hhu", &reg, &n);
    printf("%u", rotate_left(reg, n));
    return 0;
}

Solving Approach

• Limit rotation: n = n % 8
• Left shift: Move all bits left by n → reg << n
• Right shift: Move bits that overflowed to right → reg >> (8 - n)
• Combine: OR the two results → ((reg << n) | (reg >> (8 - n))) & 0xFF