How to make home security system using Arduino Uno

#include <LiquidCrystal.h>  // defining the library for LCD
#include <Keypad.h>    // defining the library for keypad
LiquidCrystal lcd(A1, A0, 5, 4, 3, 2);// Arduino pins for LCD
#define Password_Length 9 // defining the  password length
char userInput[Password_Length];/*string for storing  the user input*/
char Master[Password_Length] = "1234"; /*saving the correct password*/
char customKey;// This variable holds key input of every key pressed
byte pressCount = 0;/* for storing the counter for the amount of times the keys are pressed*/
const byte ROWS = 4; // defining number of rows
const byte COLS = 4; // defining number of columns
int led = A2;// Arduino pin for green LED
int led2 =A3;// Arduino pin for red LED

char keys [ROWS] [COLS]= // assigning values to keys of the keypad
{
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}

};
// C key is used for  CLEAR and A key is used to ENTER the password

byte rowPins[ROWS] = {13,12,11,10}; //Arduino pins for rows of keypad
byte colPins[COLS] = {9,8,7,6}; // Arduino pins for columns of keypad
Keypad customKeypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );// mapping the values to the respective keys of keypad

void setup() {
  lcd.begin(16,2);// initializing the dimensions of LCD
  lcd.setCursor(0,0);// setting the place for the data to be displayed
  lcd.print("  Arduino Home ");// data to be displayed
  lcd.setCursor(0,1);// setting the place for the data to be displayed
  lcd.print(" Security System");// data to be displayed
  delay(2000);// time for which the data will be displayed
  lcd.clear();// clearing the LCD
  pinMode(led,OUTPUT);
  pinMode(led2,OUTPUT);
  digitalWrite(led2,LOW); //assigning LOW state to Red LED
}
void loop() {

  lcd.setCursor(0,0); //setting the place for the data to be displayed
  lcd.print("Enter Password:");         //asking for entering the password                            
  customKey = customKeypad.waitForKey();  // waiting for the user to enter the password                            

  if (customKey != NO_KEY && customKey != 'C' && customKey != 'A') /* If key other than clear function and equal to function is pressed*/
  {
  userInput[pressCount] = customKey;/* count the keys with the integer values pressed */
  lcd.setCursor(pressCount + 4, 1); /*setting the place where the password will be displayed on LCD*/
  lcd.print("*");   // displaying the Asterisk against each password key
  pressCount++; // increment one in the count of length of password that is 4
  }

  else if (customKey == 'C')  // if the key having clear function C is pressed
  {                            
  lcd.clear();// then clear the LCD
  clearData();
  }

  else if (customKey == 'A') /* if the key is pressed and the password count is less than 4 then clear the LCD and display invalid password*/
  {                            
  lcd.clear();                  
  lcd.setCursor(0,0);
  lcd.print("Invalid Password!");// display its an invalid password
  delay(2000);
  clearData();
  }  
  if (pressCount == 4)       /*if the 4 value password is entered then match the user input with given password */  
  {                          
  lcd.clear();
  waitHere();  // function that displays the password in asterisk                
  }
}

void waitHere(){
  lcd.setCursor(0,0);
  lcd.print(" Enter Password:");
  lcd.setCursor(0,1);
  lcd.print("    ****");                  
                                               
customKey = customKeypad.waitForKey();       // waiting for the user to press the equal to key
 
  if (customKey != NO_KEY && customKey == 'A')  /*if the enter key is pressed the program will match the password entered by the user*/
  {
  lcd.clear();
  lcd.setCursor(0,0);
 if (!strcmp(userInput, Master)) // user input is matched then grant the access
    {                                        
    lcd.setCursor(0,0);
    lcd.print("ACCESS GRANTED");
    digitalWrite(led,HIGH);// turn the green LED on
    delay(1000);
    clearData();
    }
    else if (strcmp(userInput, Master))  /*if password is not matched then deny the access*/
    {                                          
    lcd.setCursor(0,0);
    lcd.print("ACCESS DENIED");
    digitalWrite(led2,HIGH);//turn the red LED on
    delay(2000);
    clearData();
    }
  }
/* conditions for each key pressed on the keypad for each key other than clear and enter the wait here function is used to display it on LCD*/
  if (customKey != NO_KEY && customKey == 'C')  
  {
  lcd.clear();
  clearData();
  }
 
  if (customKey != NO_KEY && customKey == '0')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '1')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '2')
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '3')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '4')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '5')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '6')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '7')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '8')  
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '9')
  {
  waitHere();
  }
}
// function assigned to key C of keypad for clearing the LCD
void clearData() {  
  while (pressCount != 0)
  {
  userInput[pressCount--] = 0;    // decrements the value entered to zero
  digitalWrite(led,LOW);
  setup();            // calling the setup function to restart the program
}
}