70. Packet Layout Using Union with Struct

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

// Packet
typedef union {
    uint8_t arr[6]; 
    struct {
        uint8_t start; 
        uint8_t cmd; 
        uint16_t data; 
        uint8_t crc;
        uint8_t end;  
    } bytes;
} Packet; 

// Fill struct fields and print raw bytes
void build_and_print_packet(uint8_t s, uint8_t c, uint16_t d, uint8_t crc, uint8_t e) {
    Packet p; 
    p.bytes.start = s; 
    p.bytes.cmd = c; 
    p.bytes.data = d; 
    p.bytes.crc = crc; 
    p.bytes.end = e; 

    for (int i = 0; i < 6; i++)
    {
        printf("%u", p.arr[i]); 
        if (i < 5) printf(" ");
    }

}

int main() {
    uint8_t s, c, crc, e;
    uint16_t d;
    scanf("%hhu %hhu %hu %hhu %hhu", &s, &c, &d, &crc, &e);
    build_and_print_packet(s, c, d, crc, e);
    return 0;
}