79. Extract Packet Fields from Byte Stream

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

typedef struct {
    uint8_t start;
    uint8_t command;
    uint16_t data;
    uint8_t crc;
    uint8_t end;
} Packet;

typedef union {
    uint8_t data[6];
    Packet pkt;
}Stream;

void print_packet_fields(uint8_t *buffer) {
    // Overlay struct and print values
    Stream payload;

    memcpy(payload.data, buffer, sizeof(payload.data));

    printf("Start: %d\n",   payload.pkt.start);
    printf("Command: %d\n", payload.pkt.command); 
    printf("Data: %d\n",    payload.pkt.data);
    printf("CRC: %d\n",     payload.pkt.crc);
    printf("End: %d\n",     payload.pkt.end);   
}

int main() {
    uint8_t buffer[6];
    for (int i = 0; i < 6; i++) {
        scanf("%hhu", &buffer[i]);
    }
    print_packet_fields(buffer);
    return 0;
}