Set Specific Bits in a 32-bit Register

Code

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

uint32_t set_bits(uint32_t reg, uint8_t start, uint8_t len) {
    // Create mask with len bits set
    uint32_t mask = ((1U << len) - 1) << start;
    // Set bits using OR
    return reg | mask;
}

int main() {
    uint32_t reg;
    uint8_t start, len;

    scanf("%u %hhu %hhu", &reg, &start, &len);
    printf("%u", set_bits(reg, start, len));

    return 0;
}

Solving Approach