# com_local_time
컴퓨터 시계로 우리나라 시간 및 다른 나라 시계 구현

# UNIX_EPOCH이용하여 loop하면 됩니다.

```rs
use std::{ io::Write,
    thread::sleep,
    time::{SystemTime, UNIX_EPOCH},
};

const SEC_IN_MIN: u64 = 60;
const SEC_IN_HOUR: u64 = 60 * SEC_IN_MIN;
const SEC_IN_DAY: u64 = 24 * SEC_IN_HOUR;
const SEC_IN_YEAR: u64 = 365 * SEC_IN_DAY;
const SEC_IN_LEAP_YEAR: u64 = 366 * SEC_IN_DAY;

fn is_leap_year(year: u64) -> bool {
    (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)
}

fn main() {
    loop {
        let total_sec: u64 = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .expect("Time went backwards")
            .as_secs();

        let mut remaining_sec = total_sec;

        // Calculate the current year
        let mut year = 1970;
        while remaining_sec >= SEC_IN_YEAR {
            let year_seconds = if is_leap_year(year) {
                SEC_IN_LEAP_YEAR
            } else {
                SEC_IN_YEAR
            };
            if remaining_sec < year_seconds {
                break;
            }
            remaining_sec -= year_seconds;
            year += 1;
        }

        // Calculate the current month and day
        const DAYS_IN_MONTH: [u64; 12] = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
        const DAYS_IN_LEAP_MONTH: [u64; 12] = [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
        const DAYS_OF_WEEK: [&str; 7] = ["월", "화", "수", "목", "금", "토", "일"];

        let days_in_month = if is_leap_year(year) {
            &DAYS_IN_LEAP_MONTH
        } else {
            &DAYS_IN_MONTH
        };

        let mut month = 0;
        let mut days = remaining_sec / SEC_IN_DAY;
        remaining_sec %= SEC_IN_DAY;

        while month < 12 && days >= days_in_month[month] {
            days -= days_in_month[month];
            month += 1;
        }

        // Calculate the current hour, minute, and second
        let hours = remaining_sec / SEC_IN_HOUR;
        remaining_sec %= SEC_IN_HOUR;
        let minutes = remaining_sec / SEC_IN_MIN;
        let seconds = remaining_sec % SEC_IN_MIN;

        let day_of_week_cal = (days + 2) % 7;
        let week_cal = DAYS_OF_WEEK[day_of_week_cal as usize];

        print!(
            "\r{}년 {}월 {}일 {}요일, {}: {}: {}",
            year,
            month + 1,
            days + 1,
            week_cal,
            hours + 9,
            minutes,
            seconds,
        );
        std::io::stdout().flush().unwrap();
        sleep(std::time::Duration::from_secs(1));
    }
}


```

# Result

```bash
2024년 6월 3일 금요일, 19: 41: 19
```