#include <Keypad.h> //include keypad library
#include <LiquidCrystal.h> //include LCD library

//define keypad pins
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char keys[ROWS][COLS] = { //define keypad keys
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

//initialize keypad and LCD
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS);
LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2);

void setup(){
  lcd.begin(16, 2); //set LCD to 16x2 characters
}

void loop(){
  char key = keypad.getKey(); //read keypad input
  if (key != NO_KEY){ //if a key is pressed
    lcd.print(key); //print key to LCD
    delay(500); //delay to prevent multiple key presses
  }
}