Extract a Bit Field from a 32-bit Register

Code

#include<stdio.h>
#include<stdint.h>
uint32_t field(uint32_t reg, uint8_t pos, uint8_t len){
    return (reg >> pos) & ((1U << len) - 1);
}
int main(){
    uint32_t reg;
    uint8_t pos, len;
    scanf("%u %hhu %hhu", &reg, &pos, &len);
    printf("%u", field(reg,pos,len));
    return 0;
}

Solving Approach