17. Extract the Nibble from an 8-bit Register

#include <stdio.h>
#include <string.h>


unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here

    if (pos == 0) {
        // 掩码操作：保留低4位
        return (reg & 0x0F);
    } else if (pos == 1) {
        // 移位+掩码：右移4位后保留结果
        return ((reg >> 4) & 0x0F);
    }
    return 0; // 错误处理
}


int main() {
    unsigned char reg;
    int pos;
    scanf("%hhu %d", &reg, &pos);
    printf("%d", extractNibble(reg, pos));
    return 0;
}