#include <Keypad.h>

// keypad
const byte ROWS = 3;
const byte COLS = 3;

char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'}
};

byte rowPins[ROWS] = {12, 11, 10};
byte colPins[COLS] = {2, 3, 4};

Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

void setup(){
  Serial.begin(9600);
}

void loop(){
  char key = keypad.getKey();
  
  if (key){
    Serial.print("Key Pressed : ");
    Serial.println(key);
  }
}