#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins [ROWS] = { 9, 8, 7, 6};
byte colPins [COLS] = { 5, 4, 3, 2};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

const int buzzer = 12;

void setup() {
  lcd.init();
  lcd.backlight();
}

void loop() {
  char safe = keypad.getKey();
  if(safe != NO_KEY){
    lcd.setCursor(0,1);
    lcd.print(safe);
    digitalWrite(buzzer, HIGH);
  }
  if (safe == 'C') {
    lcd.clear();
  }
}


/* 
variable A = 1
variable B = 2

if (A == B) EQUALS
if (A != B) DOES NOT EQUAL

delay(1000);
lcd.noBacklight()

int a = 2
char b = 'C'



int: integer

int = 1

String: words, sentences

String myString = "this  is a string"
String name = "Chris"
String city = "Atlantis"
String sentence = "hello, world"

bool: true/False values

bool skyIsRed = false;
bool skyIsBlue = true;
bool backlightEnabled = true;
bool doorIsOpen = false;

char: a single letter, digit, or symbol 

char myLetter = "A"s
char thisIsACharacter = 'B'

byte: numbers from 0 to 255 (uses less memory than int)

*/