/*Write a program to interface LCD and keypad (4 X 4) , to exhibit the functionality of a 
basic calculator.
1 2 3 4 
5 6 7 8
9 0 + -
/ * Clear Enter*/
#include <keypad.h>
byte rows=4;
byte cols=4; 
char keys[rows][cols]={
   {'1','2','3','4'}
   {'5','6','7','8'}
   {'9','0','+','-'}
   {'/','*','Clear','Enter'}
};
keypad keypad =keypad(makekeymap(keys)),rpins,cpins,rows,cols);

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

void loop() {
 char key=keypad.getkey();
 if (key!=no_key)
 Serial.println(println(key));
}