#include <LiquidCrystal.h>
#include <Keypad.h>

LiquidCrystal lcd(13, 12, 11, 10, 9, 8);

const int greenLed = 7;
const int redLed = 6;
const int rows = 4;
const int cols = 4;

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

byte rowPins[rows] = {0, 1, 2, 3};
byte colPins[cols] = {A0, A1, A2, A3};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, rows, cols);

const int password = 1234;
int inputPassword = 0;

void setup() {
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  lcd.print("Enter Password:");
  lcd.setCursor(0, 1);
}

void loop() {
  char key = keypad.getKey();

  if(key >= '0' && key <= '9') {
    inputPassword = inputPassword * 10 + (key - '0');
    lcd.print('*');
  }

  else if(key == '#') {
    if(password == inputPassword){
      digitalWrite(greenLed, HIGH);
    }

    else {
      digitalWrite(redLed, HIGH);
    }
  }
}