27. Extract Bit Field from 16-bit Register

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

#define GET_FIELD(reg, pos, mask) \
            ((reg & (mask << pos)) >> pos)

uint8_t extract_field(uint16_t reg) {
    return GET_FIELD(reg, 4, 0b11111);
}

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