1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode);

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

unsigned char modifyBit(unsigned char reg, int pos, int mod)
{
    unsigned char regTemp = (unsigned char)0X00;

    if (mod == 1){
        regTemp = 1 << pos;  
        return (reg | regTemp);
    }
    else{
        regTemp = 1 << pos;  
        return (reg ^ regTemp);
    }
}