Serialized Data Buffer

Code

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

void store2byte(uint8_t* dest, uint16_t value) {
    *dest = value & 0xff;
    *(++dest) = (value >>= 8) & 0xff;
}

void store4byte(uint8_t* dest, uint32_t value) {
    *dest = value & 0xff;
    *(++dest) = (value >>= 8) & 0xff;
    *(++dest) = (value >>= 8) & 0xff;
    *(++dest) = (value >>= 8) & 0xff;
}

void fill_buffer(uint8_t* buffer, uint8_t cmd, uint16_t value, uint8_t status, uint32_t checksum) {
    buffer[0] = 0xa5;
    buffer[1] = cmd;
    store2byte(&buffer[2], value);
    buffer[4] = status;
    store4byte(&buffer[5], checksum);
    buffer[9] = 0x5a;
}

void print_buffer(uint8_t * buffer) {
    uint8_t * tail = buffer + 10;
    for( uint8_t * base = buffer; base < tail; base++ ) {
        if(base != buffer) {
            printf(" ");
        }
        printf("%hhu", *base);
    }
}

void build_packet(uint8_t command, uint16_t value, uint8_t status, uint32_t checksum) {
    uint8_t buffer[10];

    fill_buffer(buffer, command, value, status, checksum);
    print_buffer(buffer);

    // Your logic to fill buffer
    // Then print buffer
}

int main() {
    uint8_t cmd, status;
    uint16_t val;
    uint32_t crc;

    scanf("%hhu %hu %hhu %u", &cmd, &val, &status, &crc);
    build_packet(cmd, val, status, crc);
    return 0;
}

Solving Approach