Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    if (pos == 0) {
        // Lower nibble (bits 0-3)
        return reg & 0x0F;
    } else if (pos == 1) {
        // Upper nibble (bits 4-7)
        return (reg >> 4) & 0x0F;
    } else {
        // Invalid position, return 0
        return 0;
    }
}

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

Solving Approach

1. Read input:
   • An 8-bit unsigned value (reg)
   • Nibble position (pos)
2. Extract nibble using bitwise operations:
   • If pos == 0:
      Extract lower nibble: reg & 0x0F
   • If pos == 1:
      Extract upper nibble: (reg >> 4) & 0x0F
3. Return/print the nibble in decimal (0–15)