19. Extract a Bit Field from a 32-bit Register

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

uint32_t extract_field(uint32_t reg, uint8_t pos, uint8_t len) {
    // Your code here
    uint32_t ans;
    // directly create the answer
    // the bit = ((reg>>pos)&1) put this into ans from 0th index
    for(int i=pos;i<pos+len;i++) {
        ans|= (((reg>>i)&1)<<(i-pos));
    }
    return ans;
}

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;
}