4x4 Keypad For Arduino

//Using 4x4-Keypad With Serial Monitor

#include <Keypad.h>
const byte ROWS = 4;
const byte  COLS = 4;
char keys [ROWS] [COLS] =
{ {'1', '2', '3', 'A' },
   {'4', '5', '6', 'B' },
   {'7', '8', '9', 'C' },
   {'*', '0', '#', 'D' } };
byte rowPins [ROWS] = {2, 3, 4, 5};
byte colPins [COLS] = {6, 7, 8, 9};
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS);

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

void loop( )
{
char key = keypad.getKey( );
 if (key != NO_KEY)
{
Serial.print(key);
}
}