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); // Set bit
   } 
   if(mode==0)
   {
    reg &=~(1<<pos); // Clear bit
   }
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;
}