20. Clear Specific Bits in a 32-bit Register

#include <stdio.h>
#include <stdint.h>

uint8_t createMask(uint8_t len) {
    uint8_t mask = 0;

    len--;
    while(len) {
        mask |= (1 << len);
        len--;

        if (len == 0)
            mask |= (1 << len);
    }

    return mask;
}

uint32_t clear_bits(uint32_t reg, uint8_t pos, uint8_t len) {
    // Your code her
    uint8_t mask = createMask(len);
    return reg & ~(mask << pos);
}

int main() {
    uint32_t reg;
    uint8_t pos, len;
    scanf("%u %hhu %hhu", &reg, &pos, &len);
    printf("%u", clear_bits(reg, pos, len));
    return 0;
}