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) {
    // 1. Calculate the number of bits to set
    // 2. Create a mask: (1 << count) - 1 creates 'count' number of 1s
    // 3. Shift the mask to the 'start' position
    uint8_t mask = ((1 << (end - start + 1)) - 1) << start;
    
    // 4. Combine with original register using OR
    return reg | mask;
}

int main() {
    uint8_t reg, start, end;
    // Using %hhu for unsigned char (8-bit integer) input
    if (scanf("%hhu %hhu %hhu", &reg, &start, &end) == 3) {
        printf("%u\n", set_range(reg, start, end));
    }
    return 0;
}