#include <Keypad.h>

const uint8_t ROWS = 4;
const uint8_t COLS = 3;
char keys[ROWS][COLS] = {
  { '1', '2', '3' },
  { '4', '5', '6' },
  { '7', '8', '9' },
  { '*', '0', '#' }
};

uint8_t colPins[COLS] = { 5, 4, 3 }; // Pins connected to C1, C2, C3
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; // Pins connected to R1, R2, R3, R4

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

void setup() {
    keypad.addEventListener(keypadEvent);  // Add an event listener for this keypad

  Serial.begin(9600);
}

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

  if (key != NO_KEY) {
    Serial.println(key);
  }
}

// Taking care of some special events.
void keypadEvent(KeypadEvent key) {
  switch (keypad.getState()) {
    case PRESSED:
      // if (key == '#') {
      //   digitalWrite(ledPin, !digitalRead(ledPin));
      //   ledPin_state = digitalRead(ledPin);  // Remember LED state, lit or unlit.
      // }
      break;

    case RELEASED:
      // if (key == '*') {
      //   digitalWrite(ledPin, ledPin_state);  // Restore LED state from before it started blinking.
      //   blink = false;
      // }
      break;

    case HOLD:
      if (key == '*') {
      
        for (int r = 0; r < 4; r++) {
          for (int c = 0; c < 3; c++) {
            Serial.println(keys[r][c]);
          }
        }
      }
      break;
  }
}