Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    if(pos==0){
        return(reg & 0x0F);
    }
    
    if(pos==1){
        return (reg & 0xF0)>>4;
    }
}

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

//unsigned char = uint8_t

Solving Approach