arduino 万年历代码

以下是一个简单的Arduino万年历代码示例，可以显示当前日期和时间，支持闰年和平年的计算：

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C LCD

byte daysInMonth[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; // days in each month
String daysOfWeek[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}; // days of the week

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Calendar");
}

void loop() {
  int year = 2021; // current year
  int month = 1; // current month
  int day = 1; // current day
  int hour = 0; // current hour
  int minute = 0; // current minute
  int second = 0; // current second
  int dayOfWeek = 0; // current day of week
  int daysInYear = 365; // days in a year

  // check for leap year
  if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
    daysInYear = 366;
  }

  // calculate day of the year
  int dayOfYear = 0;
  for (int i = 0; i < month - 1; i++) {
    dayOfYear += daysInMonth[i];
  }
  dayOfYear += day;

  // calculate day of the week
  dayOfWeek = (dayOfYear + (year - 1) * daysInYear + (year - 1) / 4 - (year - 1) / 100 + (year - 1) / 400) % 7;

  // print date and time
  lcd.setCursor(0, 1);
  lcd.print(daysOfWeek[dayOfWeek]);
  lcd.print(" ");
  lcd.print(month);
  lcd.print("/");
  lcd.print(day);
  lcd.print("/");
  lcd.print(year);
  lcd.print(" ");
  lcd.print(hour);
  lcd.print(":");
  lcd.print(minute);
  lcd.print(":");
  lcd.print(second);

  delay(1000);
}

此代码使用I2C LCD显示当前日期和时间，可以根据需要进行修改。