30.09 1

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

const uint32_t YEAR_MAX = 2000;

typedef struct  {
    uint8_t day: 5;
    uint8_t year: 3;
    uint8_t month_1: 4;
    uint8_t month_2: 4;
} date;

date new_date(const uint8_t day, const uint8_t month, const uint8_t year) {
    const date d = { .day = day, .month_1 = month << 2, .month_2 = month >> 2, .year = year };
    return d;
}

int main() {
    uint8_t day = 0, month = 0, year = 0;

    puts("Day, Month, Year from 2000: ");
    scanf("%u%u%u", &day, &month, &year);

    const date d = new_date(day, month, year);
    printf("day: %u, month: %u, year: %u, size: %lu", d.day, ((d.month_1 >> 2) + (d.month_2 << 2)), d.year + YEAR_MAX, sizeof(d));

    return 0;
}