int x = 0;
int a = 0;
int b = 0;

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

#include <Keypad.h>
const uint8_t ROWS = 4;
const uint8_t COLS = 4;
char keys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[COLS] = { 26, 25, 33, 32 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 13, 12, 14, 27 }; // Pins connected to R1, R2, R3, R4

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

int pwa[4];    //輸入的數字轉成函數
int pw[4];     //隨機4位數的函數

String input_password;

void setup() {
  Serial.begin(9600);

  input_password.reserve(32);

  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 1);
  lcd.print("welcome to 1A2B");


  ra();


}

void loop() {
  delay(10);

  char key = keypad.getKey();
  lcd.setCursor(0, 0);
  lcd.print(input_password);

  const String password = String(pw[0]) + String(pw[1]) + String(pw[2]) + String(pw[3]);
  //把函數轉成字串後相加

  if (key) {

    if (key == '*') {
      input_password = ""; // clear input password
      lcd.init();
    }

    else if (key == '#') {
      a2b();
      lcd.init();

      if (password == input_password) {
        Serial.println(input_password + "  The password is correct, ACCESS GRANTED!");
        lcd.setCursor(0, 1);
        lcd.print(input_password+" you win !!!");        // DO YOUR WORK HERE
        a=0;     //把A跟B的記憶洗掉
        b=0;     
      }

      else {
        Serial.println(input_password + " " +String(a)+"A"+String(b)+"B");
        lcd.setCursor(0, 1);
        lcd.print(String(a)+"A"+String(b)+"B");
        input_password = ""; // clear input password
        a=0;
        b=0;
      }
      input_password = ""; // clear input password
    }

    else {
      input_password += key; // append new character to input password string

      int intpw = input_password.toInt();     //把input_password轉成整數

      pwa[0] = intpw / 1000;
      pwa[1] = (intpw - pwa[0] * 1000) / 100;
      pwa[2] = (intpw - pwa[0] * 1000 - pwa[1] * 100) / 10;
      pwa[3] = (intpw - pwa[0] * 1000 - pwa[1] * 100 - pwa[2] * 10);

      for (int i = 0; i < 4; i++)
      {
        Serial.print(pwa[i]);
      }

      Serial.println("");
    }
  }
}
void ra()     //隨機陣列
{

  for (int i = 0; i < 4; i++)
  {
    x = random(0, 9);
    while (x == pw[0] or x == pw[1] or x == pw[2] or x == pw[3])
    {
      x = random(0, 9);
    }
    pw[i] = x;
  }

  for (int i = 0; i < 4; i++)
  {
    Serial.print(pw[i]);
  }

  Serial.println("");
}
void a2b()     //1A2B的判斷
{

  for(int i=0;i<4;i++)
  {
    for(int j=0;j<4;j++)
    {
      if(pwa[i]==pw[j])
      {
        if(i==j)
        {
          a+=1;
        }
        else
        {
          b+=1;
        }
      }
    }
  }
}