1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    unsigned char mask=1;//0000 0001
     mask=mask<<pos;
    if(mode==1)
        return (reg | mask);// 0000 1010 | 0000 1000 = 0000 1010
    else
    if(mode==0)
        return (reg & ~mask);// 0000 1010 & 1111 0111 = 0000 0010
    
}

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