Set or Clear a Specific Bit in a Register

Code

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    unsigned char a = 2;
    if(pos > 0)
    {
        for(int i = 0; i < (pos-1); i++)
        {
            a = a*2;
        }
    }
    if(pos == 0)
    {
        a = 1;
    }

    //unsigned char s = 2^pos;
    unsigned char c = ~a;

    // Write your code here
    if(mode == 1) //set
    {
        reg = reg | a;
    }
    else if(mode == 0) //clear
    {
        reg = reg & c;
    }
    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;
}

Solving Approach