Set Specific Bits in a 32-bit Register

Code

#include <stdio.h>
#include <stdint.h>
uint32_t set_bits(uint32_t reg, uint8_t pos, uint8_t len) {
    int a;
    for(a=1;a<=len;a++){
    reg |= (1 << pos);
    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;
}

Solving Approach