18. Set Multiple Bits in 8-bit Register

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

uint8_t set_range(uint8_t reg, uint8_t start, uint8_t end) {
    // Solution 1:
    // for(uint8_t i = start; i <= end; i++){
    //     reg |= (1 << i);
    // }

    // Solution 2:
    uint8_t allHIGH = ((1 << (end - start + 1)) - 1);
    uint8_t mask = allHIGH << start;
    return reg | mask;
}

int main() {
    uint8_t reg, start, end;
    scanf("%hhu %hhu %hhu", &reg, &start, &end);
    printf("%u", set_range(reg, start, end));
    return 0;
}