1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

 unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    if(mode == 1)
        reg |= (1 << pos);
    else
        reg &= ~ (1 << pos);
    return reg;
}
    
int main() {
    unsigned char reg,ret;
    int pos, mode;
    scanf("%hhu %d %d", &reg, &pos, &mode);
    ret = modifyBit(reg, pos, mode);
    printf("%u\n",ret);
    return 0;
}