Set Specific Bits in a 32-bit Register

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

uint32_t set_bits(uint32_t reg, uint8_t pos, uint8_t len) {
    // Your code here
    switch(len){
        case 1: len = 1;
                break;
        case 2: len = 3;
                break;
        case 3: len = 7;
                break;
        case 4: len = 0xf;
                break;
        case 5: len = 0x1f;
                break;
        case 6: len = 0x3f;
                break;
        case 7: len = 0x7f;
                break;
    

    }
    reg &= ~((len) << pos);
    reg |= ((len)<< pos);
    return reg;
}

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