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

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);


const int ROW_NUM = 4; //four rows
const int COLUMN_NUM = 4; //four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3', '+'},
  {'4','5','6', '-'},
  {'7','8','9', '*'},
  {'.','0','=', '/'}
};

byte pin_rows[ROW_NUM] = {5, 4, 3, 2}; //connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {A3, A2, A1, A0}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );

String noOfElements;

int cursorColumn = 0;
int cursorRowInput = 1;

int n;

void setup(){
  Serial.begin(9600);
  //input_password.reserve(32); // maximum input characters is 33, change if needed
  lcd.begin(16, 2); // set up number of columns and rows
  lcd.setCursor(cursorColumn, 0);
  lcd.print("Enter#elements: ");

  //lcd.setCursor(0, 0);         // move cursor to   (0, 0)
  //lcd.print("Arduino");        // print message at (0, 0)
  //lcd.setCursor(2, 1);         // move cursor to   (2, 1)
  //lcd.print("GetStarted.com"); // print message at (2, 1)
}


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

  if (key){
    //punta sa function na mag coconvert sa inenter to integer or double
    Serial.println(key);
    lcd.setCursor(cursorColumn, 1); // move cursor to (cursorColumn, 1 ) for input
    lcd.print(key);                 // print key at (cursorColumn, 0)
    cursorColumn++;


    if(key == '/') {
      noOfElements = ""; // clear input noOfElements
    } 
    
    else if(key == '=') {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("Enter#");
      Serial.println(noOfElements);
      noOfElements = ""; // clear input noOfElements

      
    } else {
       noOfElements += key;// append new character to input noOfElements string
    }
  }
}