Extract a Bit Field from a 32-bit Register

Code

#include<stdio.h>
int main()
{
    unsigned int reg;
    int  pos , len ;
    scanf("%u %d %d ",&reg,&pos,&len);
    int i;
//pos=28

        reg=reg>>pos;// 0
        reg&=(1U <<len)-1; //4-1=3
         printf("%u",reg);
    return 0;
}

Solving Approach