// LCD1602 to Arduino Uno connection example

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

unsigned long time_passed = 0; // hour, min, sec;
unsigned long last_second = 0;

enum Page {CLOCK,  STOPWATCH};

void print_clock() {
  lcd.clear();
  auto time_stamp = time_passed;
  auto seconds = time_stamp % 60;
  time_stamp /= 60;
  auto minutes = time_stamp % 60;
  time_stamp /= 60;
  auto hours = time_stamp % 24;

  time_passed %

  lcd.print(hours);
  lcd.print(':');
  lcd.print(minutes);
  lcd.print(':');
  lcd.print(seconds);
  
}

void setup() {
  lcd.begin(16, 2);
}

void loop() {
  auto current_time = millis();
  auto elapsed_time = current_time - last_second;

  if (elapsed_time > 1000){
    last_second = current_time;
    time_passed++;
    print_clock();
  }
}