Clear Specific Bits in a 32-bit Register

#include <stdio.h>
#include <stdint.h>
uint32_t clear_bits(uint32_t reg, int pos,int len){
    uint32_t mask=((1U<<len)-1)<< pos;
    reg &=~mask;
    return reg;
}
int main(){
    uint32_t reg;
    int pos,len;
    scanf("%u %d %d", &reg,&pos,&len);
    printf("%u", clear_bits(reg,pos,len));
    return 0;
}