27. Extract Bit Field from 16-bit Register

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

uint8_t extract_field(uint16_t reg) {
    // Your logic here
    uint8_t pos1 = 4;
    uint8_t pos2 = 8;
    uint8_t bits = pos2-pos1 + 1; 
    uint8_t mask = (1<<bits)-1;
    mask |= (1<<(bits-1)) ;
    reg = reg>>pos1;

    return reg & mask;
}

int main() {
    uint16_t reg;
    scanf("%hx", &reg);
    printf("%u", extract_field(reg));
    return 0;
}