1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
        if (pos < 0 || pos > 7) return reg;

  
    unsigned char mask = (unsigned char)(1u << pos);

  
    if (mode)
        reg |= mask;      
    else
        reg &= (unsigned char)(~mask);  


    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;
}