Clear Specific Bits in a 32-bit Register

Code

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

uint32_t clear_bits(uint32_t reg, uint8_t pos, uint8_t len) {
#if 0    
    uint32_t left = ~0u << (pos + len);
    uint32_t right = (1u << pos) - 1;
    uint32_t mask = left | right;
    return reg & mask;
#endif
    
    //How it works

    //(1u << len) - 1 → Creates a mask of len consecutive 1s in the LSB positions.

    //<< pos → Shifts this mask to start at pos.

    // ~(...) → Inverts the mask so the target bits become 0s, all others stay 1s.

    //reg & mask → Clears the target bits in one step.
    
    return reg & ~(((1u << len) -1) << pos)
}

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

Solving Approach