#include <Keypad.h>

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

uint8_t colpins[COLS] ={5,4,3,2};
uint8_t rowpins[ROWS] ={9,8,7,6};

Keypad keypad = Keypad(makeKeymap(keys), rowpins, colpins , ROWS,COLS);

void setup() {
  Serial.begin(9600);
  // put your setup code here, to run once:

}

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

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

  // put your main code here, to run repeatedly:

}