#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
const uint8_t row = 4;
const uint8_t column = 4;

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

uint8_t columns[column] = {4, 3, 2, 9};
uint8_t rows[row] = {8, 7, 6, 5};

Keypad keypad = Keypad( makeKeymap(keys), rows, columns, row, column);

LiquidCrystal_I2C lcd(0x27, 16 ,2);

String code = "4568";
String attempt = "";
int lenght = 0;

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();

  lcd.setCursor(0,0);
  lcd.print("Password : ");
}

void loop() {

  char key = keypad.getKey();

  if(key != NO_KEY){
    attempt += key;
    lcd.setCursor(lenght,1);
    lcd.print("*");
    ++lenght;
  }
  
  if(lenght == 4){
    lcd.clear();
    lcd.setCursor(0,0);

    if(attempt == code){
      lcd.print("Code Correct");
    }else{
      lcd.setCursor(0, 0);
      lcd.print("Code Incorrect");
    }

    delay(3000);

    attempt = "";
    lenght = 0;

    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Password : ");
  }
}