//note for myself -> PLS DONT BE LAZY DONT STOP THE PROJECT
#include<Keypad.h>
#include<LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2); //create an object for lcd

const uint8_t row = 4; //const make var cannot be change. uint8_t take space just 1 byte
const uint8_t colum = 4; //its error for no researn
char keys[row][colum] = {
                        {"1", "2", "3", "+"},
                        {"4", "5", "6", "-"},
                        {"7", "8", "9", "*"},
                        {"C", "0", "=", "/"} 
                        };
uint8_t rowpin[row] = {9, 8, 7, 6}; //กำหนดขาpin row
uint8_t columpin[colum] = {5, 4, 3, 2}; //กำหนดขาpin colum
Keypad keypads = keypads(makeKeymap(keys), rowpin, columpin, row, colum);
void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight(); //turn on backlight to using it

}

void loop() {
  // put your main code here, to run repeatedly:
  char getkey = keypads.getKey();
  if (getkey) {
    lcd.print(getkey);
  }
}
/* todo list
  ???
*/