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 bit_mask = (1 << ((end - start) + 1)) - 1;
    reg = reg | (bit_mask << start);
    return reg;
}

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