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) {
//    uint8_t length = end - start + 1;
   // shift the mask with 'start' times;
//    uint8_t mask = ;
   // apply the mask to reg but you should shift it by 'start' times
   return reg | ((1U<<(end - start + 1)) -1 << start);
}

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