Set or Clear a Specific Bit in a Register

Code

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    if (mode == 1){
        // reg = 00001010
        // pos = 3
        // mode = 1
        // bit used to wise 1 = 0x01
        // set bit mean that we OR the reg with the bit used to wise 0x01 (this bit type
        //change according to type of the reg) << mean shift the bit 0x01 to the left 
        //pos index mean that 00000001 in to 00001000
        // Then 00001010 | 00001000 = 00001010 follow OR rule
        reg = reg | (0x01 << pos);
    }
    else {
        // Clear bit mean that we use AND with the NOT of the shifted wise bit, when 
        //NOT the wise bit it turn into all 1 except the bit we want the reg to
        //clear will be 0 then follow the AND rule 1 AND 0 will turn in to 0, all bit
        //AND with 1 will remain the same
        // 00001010 & ~(00001000) = 00001010 & 11110111 = 00000010
        reg = reg & ~(0x01 << pos);
    }
    return reg;
}

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

Solving Approach