1. Set or Clear a Specific Bit in a Register

#include <stdio.h>      // standard input output: scanf, print,

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    // Write your code here
    if(mode == 1)
    {
        // set bit
        reg = reg | (1<<pos);
    }
    else
    {
        // clear bit
        reg = reg & (~(1<<pos));
    }

    return reg;
}

// uint: 0 -> 2^n - 1;
// int:  -2^(n-1) -> 2^(n-1)

// char (8bit - 1byte) -> unsigned char = uint8_t
int main() {
    unsigned char reg;      // 8-bit
    int pos, mode;          // 4byte - 32bit

    scanf("%hhu %d %d", &reg, &pos, &mode);
    printf("%d", modifyBit(reg, pos, mode));

    return 0;
}