Extract a Bit Field from a 32-bit Register

Code

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

uint32_t extract_field(uint32_t reg, uint8_t pos, uint8_t len) {
    // Your code here
    unsigned int sum=0,r,i=1;
    for(int pos1=pos;pos1<pos+len;pos1++,i=i*2)
    {
        r=(reg>>pos1&1);
        sum=sum+(r*i);
    }
    return sum;
}

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

Solving Approach