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 || (mode != 0 && mode != 1)) {
        printf("Invalid input\n");
        return 1;
    }

    // Perform operation
    if (mode == 1) {
        // Set bit
        reg |= (1 << pos);
    } else {
        // Clear bit
        reg &= ~(1 << pos);
    }
    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;
}