Extract a Bit Field from a 32-bit Register

Code

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

uint32_t extract_bits(uint32_t reg, uint8_t pos, uint8_t len)
{
    uint32_t result = 0;
    uint32_t a = 1;

    for (int i = 0; i < len; i++)
    {
        // Check original bit at (pos + i)
        if (reg & (a << (pos + i)))
        {
            // Set bit i in result
            result |= (a << i);
        }
    }

    return result;
}

int main()
{
    uint32_t reg;
    uint8_t pos, len;

    scanf("%u %hhu %hhu", &reg, &pos, &len);

    uint32_t value = extract_bits(reg, pos, len);
    printf("%u", value);

    return 0;
}

Solving Approach