Set Multiple Bits in 8-bit Register

Code

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

uint8_t set_range(uint8_t reg, uint8_t start, uint8_t end) {
    uint8_t val = 0;
    while (start <= end) {
        if (end == 0) {
            val = val + (1 << end);
            break;
        }
        val = val + (1 << end);
        end --;
    }
    reg = reg | val; 
    // Your code here
    return reg;
    //uint8_t mask = ((1 << (end - start + 1)) - 1) << 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;
}

Solving Approach