// import the header files
#include <LiquidCrystal.h>
#include <Keypad.h>

// declare LCD object with pins marked
LiquidCrystal lcd(13, 12, 11, 10, 9, 8);

// define number of rows and columns
const byte ROWS = 4;
const byte COLUMNS = 4;

// initialize the cursor column to print the key pressed on the lcd
int cursorColumn = 0;

// define the buttons on the keypad
char hexaKeys[ROWS][ROWS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

// define row pins of the keypad
byte rowPins[ROWS] = {7,6,5,4};
// define column pins of the keypad
byte colPins[COLUMNS] = {3,2,1,0};

// declare object of keypad
Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLUMNS);

void setup() {
  // setup the LCD type
  lcd.begin(16, 2);
  // clear the LCD screen
  lcd.clear();
  // set the cursor at the 0th row and 0th column
  lcd.setCursor(0,0);
}

void loop() {
  // get the key pressed on the keypad by the user
  char key = customKeypad.getKey();
  // check if key is pressed
  if(key)
  {
    // set cursor in the lcd
    lcd.setCursor(cursorColumn, 0);
    // display the key pressed on the lcd
    lcd.print(key);
    // increment the cursor column
    cursorColumn = cursorColumn + 1;
    // check if the cursor has reached the end of the line
    if(cursorColumn == 16)
    {
      // clear the LCD
      lcd.clear();
      // reset cursorColumn
      cursorColumn = 0;
    }
  }
}