Bit Spreading Interleave Bits with Zeros

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

uint16_t spread_bits(uint8_t val) {
    uint16_t result = 0x0;
    uint16_t target = 0x0;
    
    for (unsigned i = 0; i < 8; i++) {
        target = (val >> i) & 1U;
        result |= (target << (2 * i));
    }

    return result;
}

int main() {
    uint8_t val;
    scanf("%hhu", &val);

    uint16_t result = spread_bits(val);
    printf("%u", result);
    return 0;
}

Extract the target bit by shifting it down to bit position 0 (e.g., >> i).

Then add it to the result (by OR-ing) after shifting it to the target position (doubled).